Q1.
(a)
Write down the symbols for
lithium ................................................................................
fluorine ...............................................................................
(2)
(b)
The electronic structure of a lithium atom can be shown like this:
In a similar way, complete this diagram to show the electronic structure of a fluorine atom.
(1)
(c)
A lithium atom can lose one electron to form a lithium ion which can be written (2)+
A fluorine atom can gain one electron to form a fluoride ion.
Choose from the list the correct way to write the fluoride ion.
(2,6)+
(2,7)+
(2,7)-
(2,8)+
(2,8)–
Answer ..........................................
(2)
(Total 5 marks)
Q2.
(a) The diagrams below show the electronic structure of a magnesium atom and a
magnesium ion.
What is the charge on the magnesium ion? ...............................................................
(2)
Page 1 of 141
(b)
Calcium bromide has the formula CaBr2.
What does this tell you about the ions in this compound?
....................................................................................................................................
....................................................................................................................................
(2)
(Total 4 marks)
##
Atoms of calcium, phosphorus and fluorine are represented below, each with its mass
number and proton number.
(a)
Use this information to complete the table.
CALCIUM
Number of protons in the nucleus
20
Number of neutrons in the nucleus
20
PHOSPHOROUS
Number of electrons
FLUORINE
9
16
15
9
(3)
(b)
Calcium and fluorine atoms can combine to form the compound calcium fluoride, CaF2.
The fluoride ion is represented by F–.
(i)
Explain how the fluorine atom forms a fluoride ion.
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
How is the calcium ion represented?
..........................................................................................................................
(2)
(c)
Phosphorus and fluorine form a covalent compound, phosphorus trifluoride.
Complete the sentences below which are about this compound.
Phosphorus trifluoride is made up of phosphorus and fluorine ................................
These are joined together by sharing pairs of ............................................... to form
phosphorus trifluoride ........................................................ .
(3)
Page 2 of 141
(d)
(i)
Sodium chloride, an ionic compound, has a high melting point whereas paraffin
wax, a molecular compound, melts easily.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
Molten ionic compounds conduct electricity but molecular compounds are nonconductors, even when liquid.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(Total 14 marks)
Q4.
(a) The chart shows the reactions of the metal calcium with water, oxygen and dilute
hydrochloric acid.
Name (i)
solution A .................................................................................................
(ii)
solid B .....................................................................................................
(iii)
gas C ........................................................................................................
(3)
Page 3 of 141
(b)
The diagrams below show the electronic structure of an atom of calcium and an atom
of oxygen.
Describe fully what happens to its electrons when:
(i)
a calcium atom forms a calcium ion. State the charge on the calcium ion formed.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
an oxygen atom forms an oxygen ion. State the charge on the oxygen ion formed.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(c)
Calcium oxide is an ionic compound. Why do ionic compounds have high melting points?
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 11 marks)
Q5.
Magnesium oxide is a compound, made up of magnesium ions and oxide ions.
(a)
What is the charge on each magnesium ion? .............................................................
(1)
Page 4 of 141
(b)
Explain how the magnesium ions get this charge.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
Q6.
Part of a reactivity series is:
(a)
Carbon is used in blast furnaces to obtain iron and zinc from their oxides, but electrolysis
has to be used to obtain aluminium from its oxide.
Draw an arrow on the reactivity series above to show where carbon fits into the series.
(1)
(b)
Predict the method of extraction used to obtain calcium from its ore and explain your
answer.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
The formula for zinc oxide is ZnO. Write a balanced equation for the extraction of zinc in
the blast furnace.
.....................................................................................................................................
(2)
(Total 5 marks)
Page 5 of 141
Q7.
(a)
The equation for the reaction that takes place when ammonium chloride is heated is:
NH4Cl(s)
ammonium chloride
NH3(g)
ammonia
+
HCl (g)
hydrogen chloride
The diagram shows how a teacher demonstrated this reaction. The demonstration was
carried out in a fume cupboard.
(i)
Apart from the gases normally in the atmosphere, which two gases would be
at X?
..................................................... and ...........................................................
(1)
(ii)
Name the white solid that has formed at Y.
..........................................................................................................................
(1)
(iii)
Why was the demonstration carried out in a fume cupboard?
..........................................................................................................................
..........................................................................................................................
(1)
(iv)
Complete the four spaces in the passage.
The chemical formula of ammonia is NH3. This shows that there is one atom of
.......................................... and three atoms of .................................. in each
......................................... of ammonia. These atoms are joined by bonds that
are formed by sharing pairs of electrons. This type of bond is called
a ............................... bond.
(4)
Page 6 of 141
(b)
Electrons, neutrons and protons are sub-atomic particles.
(i)
Complete the three spaces in the table.
Name of sub-atomic
particle
Relative mass
Relative charge
...............................
1
+1
...............................
1
0
...............................
–1
(2)
(ii)
Which two sub-atomic particles are in the nucleus of an atom?
........................................................... and ...............................................
(1)
(Total 10 marks)
Q8.
Part of the Periodic Table showing the symbols for the first twenty elements is given below.
(a)
Draw diagrams showing the arrangement of electrons (electronic structures) in:
(i)
an aluminium atom;
(ii)
a chlorine atom.
(2)
Page 7 of 141
(b)
(i)
Use electronic structures to help you show why the formula of sodium oxide is Na2O.
(3)
(ii)
State why the formation of sodium ions is classified as an oxidation.
..........................................................................................................................
..........................................................................................................................
(1)
(Total 6 marks)
Q9.
Ammonium nitrate and ammonium sulphate are used as fertilisers.
(i)
Which acid reacts with ammonia to form ammonium nitrate?
....................................................................................................................................
(1)
(ii)
Which acid reacts with ammonia to form ammonium sulphate?
....................................................................................................................................
(1)
Page 8 of 141
(iii)
The reactions in (i) and (ii) are both exothermic. How can you tell that a reaction is
exothermic?
....................................................................................................................................
....................................................................................................................................
(1)
(iv)
The reactions in (i) and (ii) are both examples of acid + base reactions. What is the name
of the chemical change which takes place in every acid + base reaction?
....................................................................................................................................
(1)
(Total 4 marks)
Q10.
(a)
Atoms are made of sub-atomic particles. Complete the six spaces in the table.
Name of sub-atomic
particle
Relative mass
.................................
Relative charge
......................
Neutron
.....................
.......................
.................................
1
.......................
(3)
(b)
Complete the spaces in the sentences.
(i)
The atomic number of an atom is the number of ..................................... in its
nucleus and is equal to the number of ..................................................... if the
atom is not charged.
(1)
(ii)
The mass number of an atom is the total number of ................................. and
...................................... in its nucleus.
(1)
Page 9 of 141
(c)
The table gives information about the atoms of three elements.
Number of electrons in:
Name of
element
Chemical
symbol
Fluorine
1st
shell
2nd
shell
3rd
shell
F
2
7
0
Neon
Ne
2
8
0
Sodium
Na
2
8
1
Two of these elements can react together to form a chemical compound.
(i)
What is the name and the formula of this compound?
Name ................................................... Formula ..........................................
(2)
(ii)
What type of bonding holds this compound together?
...........................................................................................................................
(1)
(iii)
Explain, in terms of electron transfer, how the bonding occurs in this compound.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 10 marks)
Page 10 of 141
Q11.
Electrons, neutrons and protons are sub-atomic particles.
(a)
Complete the six spaces in the following table.
Name of sub-atomic
particle
Relative mass
Relative charge
.......................................
1
........................................
.......................................
........................................
0
.......................................
.........................................
(3)
(b)
An aluminium atom has 13 electrons. How are these arranged in shells around the
nucleus?
....................................................................................................................................
(1)
(c)
Chromium atoms have 24 protons and 28 neutrons.
(i)
How many electrons does each neutral chromium atom have?
...........................................................................................................................
(1)
(ii)
What is the mass number of chromium?
...........................................................................................................................
(1)
(d)
What change occurs to an atom which undergoes the process of reduction in a chemical
reaction?
....................................................................................................................................
....................................................................................................................................
(1)
Page 11 of 141
(e)
The diagram shows part of the ionic lattice of a sodium chloride crystal.
Explain why the ions in this lattice stay in place.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
(Total 10 marks)
Q12.
(a) A piece of lithium is placed on the surface of some water in a beaker.
Hydrogen is given off.
Lithium hydroxide is also formed.
Write a word equation for this reaction.
.....................................................................................................................................
(2)
Page 12 of 141
(b)
The diagram shows the structure of a molecule of methane.
Write down everything that this diagram tells you about a methane molecule.
To gain full marks in this question you should write your ideas in good English. Put them
into a sensible order and use the correct scientific words.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 6 marks)
Q13.
Sodium chloride is an ionic compound.
(Total 2 marks)
Page 13 of 141
Q14.
Use the Data Sheet to help you answer this question.
When sodium reacts with water it forms sodium ions.
The diagrams below represent the electron arrangements of some atoms and ions.
Which of the diagrams, A to E, represents the electron arrangement of each of the following?
(i)
A sodium atom, Na .............................
(ii)
A sodium ion, Na+ ..............................
(Total 2 marks)
Q15.
Calcium and magnesium are elements. They are found in the Earth’s crust as compounds,
often carbonates and sulphates. Magnesium is also found as its chloride.
(a)
Calcium and magnesium are in the same Group in the Periodic Table.
State which Group this is.
.....................................................................................................................................
(1)
(b)
Use the Data Sheet to help you to answer this question.
(i)
Write the chemical formula of magnesium chloride.
...........................................................................................................................
(1)
(ii)
Name the type of bonding in magnesium chloride.
...........................................................................................................................
(1)
(Total 3 marks)
Page 14 of 141
Q16.
This question is about sodium chloride (common salt) which is an important chemical.
Sodium chloride can be made by burning sodium in chlorine gas.
(a)
Balance the symbol equation for the reaction of sodium with chlorine.
Na(s)
+
Cl2(g)
→
NaCl(s)
(1)
(b)
(i)
Complete the diagrams below to show the electronic structures of a sodium and a
chlorine atom. (Atomic number of sodium = 11 and chlorine = 17.)
(3)
(ii)
When sodium reacts with chlorine the sodium atoms are changed into sodium ions
(Na+) and the chlorine atoms are changed into chlorine ions (Cl–).
Explain how:
1.
a sodium atom changes into a sodium ion;
...........................................................................................................................
...........................................................................................................................
(2)
2.
a chlorine atom changes into a chloride ion.
...........................................................................................................................
...........................................................................................................................
(2)
Page 15 of 141
(c)
The element potassium is in the same group of the Periodic Table as sodium. Potassium
reacts with chlorine to make potassium chloride which is sometimes used instead of
common salt in cooking.
(i)
Predict the formula of potassium chloride.
...........................................................................................................................
(1)
By reference to the electronic structures of potassium and sodium explain:
(ii)
Why the reaction of potassium with chlorine is similar to the reaction of sodium
with chlorine.
...........................................................................................................................
...........................................................................................................................
(1)
(d)
The electrolysis of sodium chloride solution is an important industrial process. The
diagrams below show two experiments set up during an investigation of the electrolysis of
sodium chloride.
(i)
What would be the reading on the ammeter in experiment 1?
.................................................... A
(ii)
Explain your answer.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(e)
The equations below show the reactions which take place in experiment 2.
H2O(1)
→
H +(aq)
2H+(aq)
+
2e–
→
H 2(g)
2Cl–(aq)
–
2e–
→
Cl2(g)
+
OH– (aq)
Page 16 of 141
(i)
Which substance provides hydrogen ions?
...........................................................................................................................
(1)
(ii)
Name the product formed at:
(A)
the positive electrode;
...........................................................................................................................
(B)
the negative electrode.
...........................................................................................................................
(1)
(Total 15 marks)
Q17.
Many everyday substances can be classified as acids, bases or salts. For example, car
batteries contain sulphuric acid, oven cleaners contain sodium hydroxide and table salt contains
sodium chloride.
(a)
A solution of each of these substances was tested with universal indicator.
Solution
Sulphuric acid (H2SO4)
Colour of universal indicator
red
Sodium hydroxide (NaOH)
purple
Sodium chloride (NaCl)
green
(i)
Explain how these universal indicator colours and the corresponding pH values could
be used to identify each of these solutions.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
Name and give the formula of the ion which causes the solution to be acidic.
Name of ion ..................................................................................................
Formula of ion .................................................................................................
(2)
Page 17 of 141
(b)
Sodium chloride can be made by reacting sodium hydroxide with hydrochloric acid in the
presence of an indicator.
(i)
What is the name of this type of reaction?
..........................................................................................................................
(1)
(ii)
Write a balanced chemical equation for this reaction.
..............(aq) + ..............(aq) → ..............(aq) + ..............(l)
(2)
(c)
The atomic number for sodium is 11 and for chlorine is 17.
(i)
Complete the diagrams to show the electron arrangements for a sodium atom and a
chlorine atom.
(2)
(ii)
These atoms form different particles by one electron transferring from the sodium
atom to the chlorine atom. What is the name given to the particles formed?
...........................................................................................................................
(1)
(iii)
Why do these sodium and chloride particles bond?
...........................................................................................................................
...........................................................................................................................
(1)
(d)
Sodium chloride solution is electrolysed to form three products, hydrogen, chlorine and
sodium hydroxide.
Page 18 of 141
Describe how each of these products are formed.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 15 marks)
Q18.
Ammonia (NH3) is an important chemical which is used to make fertilisers. Ammonia is
made from nitrogen and hydrogen,
(a)
The diagrams represent the electron arrangements in atoms of nitrogen and hydrogen.
Complete the diagram showing the arrangement of electrons in a molecule of ammonia.
(1)
(b)
Name the type of bonding which holds the nitrogen and hydrogen atoms together in an
ammonia molecule.
.....................................................................................................................................
(1)
(Total 2 marks)
Page 19 of 141
Q19.
(a)
A tin of red kidney beans contains calcium chloride as a firming agent.
Calcium chloride is an ionic compound which contains calcium ions (Ca2+) and chloride
ions (Cl–).
(i)
The diagram on the left represents the electronic structure of a chlorine atom.
Complete a similar diagram on the right to represent a chloride ion.
(2)
(ii)
Explain how a calcium atom changes into a calcium ion which has a 2+ charge.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
Cola drinks contain phosphoric acid, H3PO4. The two equations show how phosphoric acid
can be made from phosphorus.
Balance these two equations.
(i)
P4 + ........ O2 → P4O10
(1)
(ii)
P4O10 + ................ H2O → 4H3PO4
(1)
(Total 6 marks)
Page 20 of 141
Q20.
Hydrogen chloride (HCl) can be made by the reaction of hydrogen (H2) with chlorine (Cl2).
(a)
The diagrams represent molecules of hydrogen and chlorine.
Draw a similar diagram to represent a molecule of hydrogen chloride (HCl).
You need show only the outer energy level (shell) electrons.
(1)
(b)
The word equation for the reaction of hydrogen with chlorine is shown below.
hydrogen + chlorine → hydrogen chloride
Write a balanced symbol equation for this reaction.
.....................................................................................................................................
(2)
(c)
Hydrogen chloride gas reacts with magnesium to form the ionic compound called
magnesium chloride. Use the table of ions on the Data Sheet to help you to write the
formula of magnesium chloride.
.....................................................................................................................................
(1)
(d)
Why does magnesium chloride have a much higher melting point than hydrogen chloride?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
Page 21 of 141
Q21.
Toothpastes often contain fluoride ions to help protect teeth from attack by bacteria.
Some toothpastes contain tin(II) fluoride.
This compound has the formula SnF2 .
(a)
Calculate the relative formula mass (M r) of SnF2.
Relative atomic masses: F = 19; Sn = 119
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Relative formula mass (M r) = ..........................................
(2)
(b)
Calculate the percentage by mass of fluorine in SnF2.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Percentage by mass of fluorine = .......................................... %
(2)
Page 22 of 141
(c)
A tube of toothpaste contains 1.2 g of SnF2.
Calculate the mass of fluorine in this tube of toothpaste.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Mass of fluorine = .......................................... g
(1)
(d)
The diagram represents the electron arrangement of a fluorine atom.
Explain how a fluorine atom can change into a fluoride ion, F–.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 7 marks)
Q22.
The electrolysis of sodium chloride solution produces useful substances.
(a)
Explain the meaning of electrolysis.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 23 of 141
(b)
The diagram shows an apparatus used for the electrolysis of sodium chloride solution.
Reproduced with the permission of Nelson Thornes Ltd from PATRICK FULLICK et al, ISBN 0-74879644- 4. First published in 2006
The electrolysis produces two gases, chlorine and Gas A.
Name Gas A ...............................................................................................................
(1)
(c)
The electrodes used in this process can be made of graphite. Explain why graphite
conducts electricity.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Page 24 of 141
Q23.
Read this passage about metals.
Metals are crystalline materials. The metal crystals are normally about 20 000 nm
(nanometres) in diameter. The atoms inside these crystals are arranged in layers.
A new nanoscience process produces nanocrystalline metals. Nanocrystalline metals are
stronger and harder than normal metals.
It is hoped that nanocrystalline metals can be used in hip replacements.
The use of nanocrystalline metals should give people better hip replacements which last
longer.
(a)
State why metals can be bent and hammered into different shapes.
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
How is the size of the crystals in nanocrystalline metals different from the size of the
crystals in normal metals?
.....................................................................................................................................
.....................................................................................................................................
(1)
Page 25 of 141
(c)
Hip joints are constantly moving when people walk.
Suggest and explain why the hip replacement made of nanocrystalline metal should last
longer than one made of normal metals.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q24.
This question is about oxygen atoms. The periodic table on the Data Sheet may help you to
answer this question.
(a)
(i)
Oxygen atoms have 8 electrons.
Complete the diagram to represent the arrangement of electrons in an oxygen atom.
Use crosses (×) to represent the electrons.
(1)
(ii)
Name the part of the oxygen atom that is labelled A on the diagram.
...........................................................................................................................
(1)
(b)
Two isotopes of oxygen are oxygen-16 and oxygen-18.
16
O
8
oxygen-16
18
8
O
oxygen-18
Page 26 of 141
Explain, in terms of particles, how the nucleus of an oxygen-18 atom is different from the
nucleus of an oxygen-16 atom.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q25.
Read the article and then answer the questions that follow.
Nanotennis!
Tennis balls contain air under pressure, which gives them their bounce. Normal tennis
balls are changed at regular intervals during tennis matches because they slowly lose
some of the air. This means that a large number of balls are needed for a tennis
tournament, using up a lot of materials.
‘Nanocoated’ tennis balls have a ‘nanosize’ layer of butyl rubber. This layer slows down
the escape of air so that the ball does not lose its pressure as quickly. The
‘nanocoated’ tennis balls last much longer and do not need to be replaced as often.
(a)
How does the ‘nanosize’ layer make the tennis balls last longer?
.....................................................................................................................................
.....................................................................................................................................
(1)
Page 27 of 141
(b)
Put a tick ( ) next to the best description of a ‘nanosize’ layer.
Description
( )
A layer one atom thick.
A layer a few hundred atoms thick.
A layer millions of atoms thick.
(1)
(c)
Suggest why using ‘nanocoated’ tennis balls would be good for the environment.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q26.
Read the article and then answer the questions.
Nanotennis!
Tennis balls contain air under pressure, which gives them their bounce. Normal tennis
balls are changed at regular intervals during tennis matches because they slowly lose
some of the air.
‘Nanocoated’ tennis balls have a ‘nanosize’ layer of butyl rubber. This layer slows down
the escape of air so that the ball does not lose its pressure as quickly.
Page 28 of 141
(a)
What is the meaning of nanosize?
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
Suggest why using ‘nanocoated’ tennis balls would be good for the environment.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
Q27.
The following steps show how to use a type of glue.
Step 1 Measure out equal amounts of the liquids from tubes A and B.
Step 2 Mix the liquids to make the glue.
Put a thin layer of the glue onto each of the surfaces to be joined.
Step 3 Assemble the pieces to be joined and then hold them together with tape.
Step 4 Leave the glue to set.
Page 29 of 141
(a)
When liquids A and B are mixed a chemical reaction takes place.
(i)
This reaction is exothermic.
State how the temperature of the mixture will change as the glue is mixed.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
When the glue sets it forms a giant covalent structure.
Explain why substances with giant covalent structures have high melting points.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
The time taken for the glue to set at different temperatures is given in the table below.
Temperature in °C
Time taken for the glue to set
20
3 days
60
6 hours
90
1 hour
Explain, in terms of particles, why increasing the temperature changes the rate of the
reaction which causes the glue to set.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 5 marks)
Page 30 of 141
Q28.
Read the information in the box and then answer the question.
Aluminium is made by the electrolysis of aluminium oxide.
Aluminium oxide is an ionic compound containing aluminium ions (Al3+) and oxide ions
(O2–).
The diagram below shows the apparatus used to electrolyse aluminium oxide.
(a)
In this question you will get marks on using good English, organising information clearly
and using specialist terms correctly.
Use information in the box and your knowledge and understanding of this process to
answer this question.
Explain, as fully as you can, how aluminium and carbon dioxide are formed in this process.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(6)
Page 31 of 141
(b)
Aluminium is a metal.
Explain why aluminium conducts electricity.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(Total 8 marks)
Q29.
Ammonia has the formula NH3
The diagrams show how electrons are arranged in nitrogen and hydrogen atoms.
(a)
Draw a diagram to show how the electrons are arranged in an ammonia molecule.
You need only show the electrons in the highest energy level.
(2)
Page 32 of 141
(b)
Ammonia is a gas at room temperature.
Explain why ammonia has a low boiling point.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(c)
Ammonia dissolves in water to form a solution with a pH of about 10.
(i)
Name the ion in the ammonia solution that causes the pH of 10.
...................................................... ion
(1)
(ii)
Ammonium nitrate is made by reacting ammonia with an acid.
Name the acid.
...................................................... acid
(1)
(d)
Instant cold packs are used to treat sports injuries.
Page 33 of 141
One type of cold pack has a plastic bag with water inside. Inside the bag is a smaller bag
containing solid ammonium nitrate.
The outer bag is squeezed so that the inner bag bursts. The pack is shaken and quickly
gets cold as the ammonium nitrate dissolves in the water.
Explain why the bag gets cold.
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(2)
(Total 8 marks)
Q30.
This drinks bottle is made of thermosoftening plastic.
Drinks bottles of this type can be recycled.
Describe and explain how the bottles can be changed into new plastic objects.
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(Total 4 marks)
Page 34 of 141
Q31.
The picture shows sodium reacting with chlorine.
The reaction forms sodium chloride, which contains sodium ions and chloride ions.
(a)
The diagrams show how electrons are arranged in a sodium atom and a chlorine atom.
Explain, in terms of electrons, what happens when sodium reacts with chlorine.
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(3)
Page 35 of 141
(b)
Explain, as fully as you can, why sodium chloride has a high melting point.
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(3)
(Total 6 marks)
Q32.
This barbecue burns propane gas.
The structure of propane is shown below.
(a)
Complete the diagram to show how the outer energy level (shell) electrons of hydrogen
and carbon are arranged in a molecule of propane.
(1)
Page 36 of 141
(b)
The graph shows how the vapour pressure of propane changes with temperature.
The vapour pressure of a liquid is the pressure of the vapour above the liquid.
(i)
Describe, as fully as you can, how the vapour pressure of propane changes with
temperature.
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(2)
(ii)
The boiling point of a liquid is the temperature at which its vapour pressure is equal to
the air pressure above the liquid.
Use the graph to find the boiling point of propane when the air pressure is 100
kilopascals.
Boiling point ................................................... °C
(1)
Page 37 of 141
(c)
Explain, in terms of molecules, why propane has a low boiling point.
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(2)
(Total 6 marks)
Q33.
Aspirin tablets have important medical uses.
A student carried out an experiment to make aspirin. The method is given below.
1.
2.
3.
4.
5.
6.
7.
8.
Weigh 2.00 g of salicylic acid.
Add 4 cm3 of ethanoic anhydride (an excess).
Add 5 drops of concentrated sulfuric acid.
Warm the mixture for 15 minutes.
Add ice cold water to remove the excess ethanoic anhydride.
Cool the mixture until a precipitate of aspirin is formed.
Collect the precipitate and wash it with cold water.
The precipitate of aspirin is dried and weighed.
Page 38 of 141
(a)
The equation for this reaction is shown below.
C7H6O3
+
salicylic acid
C4H6O3 → C9H8O4
+
CH3COOH
aspirin
Calculate the maximum mass of aspirin that could be made from 2.00 g of salicylic acid.
The relative formula mass (M r) of salicylic acid, C7H6O3, is 138
The relative formula mass (M r) of aspirin, C9H8O4, is 180
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Maximum mass of aspirin = .............................. g
(2)
(b)
The student made 1.10 g of aspirin from 2.00 g of salicylic acid.
Calculate the percentage yield of aspirin for this experiment.
(If you did not answer part (a), assume that the maximum mass of aspirin that can be
made from 2.00 g of salicylic acid is 2.50 g. This is not the correct answer to part (a).)
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Percentage yield of aspirin = .............................. %
(2)
(c)
Suggest one possible reason why this method does not give the maximum amount of
aspirin.
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(1)
Page 39 of 141
(d)
Concentrated sulfuric acid is a catalyst in this reaction.
Suggest how the use of a catalyst might reduce costs in the industrial production of
aspirin.
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(1)
(Total 6 marks)
Q34.
This drill contains an electric motor.
The diagram below shows the main parts of an electric motor.
Page 40 of 141
The carbon contacts are made of graphite. Springs push the contacts against the copper ring.
The contacts conduct electricity to the copper ring. The copper ring rotates rapidly but does not
stick or become worn because the graphite is soft and slippery.
Graphite has properties which are ideal for making the contacts in an electric motor.
Explain, in terms of structure and bonding, why graphite has these properties.
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(Total 5 marks)
Page 41 of 141
Q35.
Read the article and then answer the questions that follow.
Hydrogen fuel for cars?
Hydrogen is an excellent fuel. It can be made by the electrolysis of potassium
hydroxide solution.
Hydrogen gas can be stored under pressure in a cylinder but a leak of the gas
could cause an explosion.
It has been found that lithium nitride can absorb and then release large volumes of
hydrogen. A chemical reaction takes place between the hydrogen and the lithium
nitride. The hydrogen is held in the resulting compounds by chemical bonds.
The problem is that the rate at which hydrogen is absorbed and then released
from normal sized particles of lithium nitride is slow.
Recently scientists have made ‘nanosized’ particles of lithium nitride. These
particles absorb hydrogen in the same way as normal sized lithium nitride
particles. The ‘nanosized’ particles have the advantage that they absorb and
release the hydrogen much faster when needed in the fuel cell.
It is hoped that ‘nanosized’ particles of lithium nitride may provide a safe method
of storing hydrogen in the future.
(a)
Hydrogen is produced at the negative electrode during the electrolysis of potassium
hydroxide solution.
(i)
Why are hydrogen ions attracted to the negative electrode?
...........................................................................................................................
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...........................................................................................................................
(1)
(ii)
Potassium ions are also attracted to the negative electrode.
Explain why hydrogen gas is formed but not potassium.
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(1)
Page 42 of 141
(b)
Lithium nitride is made by reacting lithium with nitrogen.
Balance the equation for this reaction.
.......... Li + N2 → .......... Li3N
(1)
(c)
(i)
The equation for the reaction of lithium nitride with hydrogen is:
Li3N + 2H2
LiNH2 + 2LiH
What feature of this reaction allows the hydrogen to be released?
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Hydrogen stored in a fuel tank filled with lithium nitride would be safer in an accident
than a cylinder full of hydrogen.
Suggest and explain why.
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(2)
(d)
Lithium nitride is an ionic compound which contains lithium ions (Li+) and nitride ions (N3–).
(i)
The formation of a lithium ion from a lithium atom is an oxidation reaction.
Explain why.
...........................................................................................................................
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(1)
Page 43 of 141
(ii)
The diagram shows the electronic structure of a nitrogen atom.
Complete the diagram below to show the electronic structure of a nitride ion (N3–).
(1)
(Total 8 marks)
Q36.
Perfumes contain a mixture of chemicals.
The main ingredients of perfumes are a solvent and a mixture of fragrances.
Page 44 of 141
(a)
A sample of the solvent used in one perfume contained 0.60 g of carbon, 0.15 g of
hydrogen and 0.40 g of oxygen.
Relative atomic masses: H = l; C = 12; O = 16.
Calculate the empirical (simplest) formula of the solvent.
You must show all of your working to gain full marks for this question.
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(4)
(b)
Solvent molecules evaporate easily.
Explain why substances made of simple molecules evaporate easily.
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(2)
(c)
Most companies claim that their perfumes have been tested on skin. A study was made of
the tests they used. The study found that each company used different tests.
The perfumes were tested in the companies’ own laboratories and not by independent
scientists.
Some companies did not give any information about the tests that they had used.
(i)
Suggest why companies test their perfumes on skin.
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(1)
Page 45 of 141
(ii)
Did the study show that the tests made by the different companies were valid and
reliable?
Explain your answer.
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(2)
(Total 9 marks)
Q37.
(a) Write a balanced symbol equation for the reaction between magnesium (Mg) and
oxygen (O2) to form magnesium oxide (MgO).
.....................................................................................................................................
(1)
(b)
The diagram shows the electronic structure of a magnesium atom.
The atomic (proton) number of magnesium is 12.
Magnesium atom
Draw a similar diagram to show the electronic structure of an oxygen atom.
The atomic (proton) number of oxygen is 8.
(1)
Page 46 of 141
(c)
Magnesium ions and oxide ions are formed when magnesium reacts with oxygen.
The diagram shows the electronic structure of an oxide ion.
Oxide ion
Draw a similar diagram to show the electronic structure of a magnesium ion.
(1)
(d)
Magnesium oxide is a white solid with a high melting point.
Explain how the ions are held together in solid magnesium oxide.
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(2)
(e)
Indigestion tablets can be made from magnesium oxide. The magnesium oxide neutralises
some of the hydrochloric acid in the stomach.
Complete the word equation for the reaction between magnesium oxide and hydrochloric
acid.
hydrochloric acid + magnesium oxide
→
......................
+
water.
(1)
(Total 6 marks)
Page 47 of 141
Q38.
Bricks made from silica (silicon dioxide) are used to line furnaces that operate at high
temperatures.
Part of the structure of silica is shown in the diagram.
Suggest and explain why silica is used to make bricks for high-temperature furnaces. In your
answer, you should refer to the structure of, and bonding in, silica.
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(Total 4 marks)
Page 48 of 141
Q39.
Read the article about the use of nanoparticles in sun creams.
Sun creams
Many sun creams use nanoparticles. These sun creams are very good at
absorbing radiation, especially ultraviolet radiation. Owing to the particle size, the
sun creams spread more easily, cover better and save money because you use
less. The new sun creams are also transparent, unlike traditional sun creams
which are white. The use of nanoparticles is so successful that they are now used
in more than 300 sun cream products.
Some sun creams contain nanoparticles of titanium oxide. Normal-sized particles
of titanium oxide are safe to put on the skin.
It is thought that nanoparticles can pass through the skin and travel around the
body more easily than normal-sized particles. It is also thought that nanoparticles
might be toxic to some types of cell, such as skin, bone, brain and liver cells.
(a)
Explain why nanoparticles pass through the skin and travel around the body more easily
than normal-sized particles of titanium oxide.
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....................................................................................................................................
(2)
(b)
Explain why sun creams containing nanoparticles should be tested further.
....................................................................................................................................
....................................................................................................................................
(1)
(c)
Suggest why some companies that make sun creams might not want to do more tests.
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(2)
(Total 5 marks)
Page 49 of 141
Q40.
Aluminium is a useful metal.
(a)
The atomic number (proton number) of aluminium is 13.
Complete the diagram to show the electronic structure of an aluminium atom.
Use crosses (x) to represent the electrons.
(1)
(b)
Aluminium is used as the electrical conductor for overhead power cables.
Explain why metals are good conductors of electricity.
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(2)
(Total 3 marks)
Page 50 of 141
Q41.
The drawing shows a high quality wire used to make electrical connections on a hi-fi
system.
(a)
Copper is used because it is a very good conductor of electricity. Copper is a typical
metal.
(i)
Describe the structure and bonding in a metal. You may wish to draw a diagram to
help you to answer this question.
To gain full marks in this question you should write your ideas in good English. Put
them into a sensible order and use the correct scientific words.
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(3)
(ii)
Explain, by reference to your answer to part (a)(i), why copper conducts electricity.
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(1)
(iii)
Explain, by reference to your answer to part (a)(i), why copper can be drawn into
wires.
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(1)
Page 51 of 141
(b)
The copper used to make this wire is “OFC” copper. This stands for ‘oxygen free copper’.
(i)
It is thought that when molten copper is cooled and solidified it can take in some
oxygen from the air. This may slightly decrease the conductivity of the copper.
Suggest why the conductivity might be decreased.
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(2)
(ii)
To make it oxygen free, the copper is heated in an atmosphere of hydrogen.
Explain how this will remove the oxygen.
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(1)
(Total 8 marks)
Q42.
Silicon is an important element used in the electronics industry.
(a)
Silicon can be made by heating a mixture of sand (silicon dioxide) with magnesium
powder.
The equation for this reaction is shown below.
SiO2 (s)+ 2Mg (s) → 2MgO (s) + Si (s)
Calculate the mass of silicon dioxide needed to make 1 g of silicon.
Relative atomic masses: O = 16; Si = 28
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Mass = ........................................................g
(3)
Page 52 of 141
(b)
The resulting mixture of magnesium oxide and silicon is added to a beaker containing
hydrochloric acid. The silicon is then filtered from the solution.
(i)
The magnesium oxide reacts with the hydrochloric acid and forms magnesium
chloride (MgCl2) solution and water.
magnesium oxide + hydrochloric acid → magnesium chloride solution + water
Write a balanced symbol equation for this reaction, including state symbols.
..........................................................................................................................
(2)
(ii)
The gases produced are a mixture of several silicon hydrides.
One of the gases produced in the reaction is the silicon hydride with the formula SiH4.
The structure of this molecule is similar to methane, CH4.
Draw a diagram to show the bonding in a molecule of SiH4. Represent the electrons
as dots and crosses and only show the outer shell (energy level) electrons.
(1)
Page 53 of 141
(iii)
A sample of a different silicon hydride was found to contain 1.4 g of silicon and 0.15
g of hydrogen.
Calculate the formula of this silicon hydride. You must show all your working to gain
full marks.
Relative atomic masses: H = 1; Si = 28
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(4)
(iv)
The silicon hydrides react immediately they come into contact with oxygen in the air.
They burst into flames with a small explosion and give out energy.
Which letter, A to H, best describes this reaction?
Energy involved in breaking and
forming bonds
The energy released from forming new
bonds is greater than the energy needed
to break existing bonds
Activation
energy
high
low
The energy needed to break existing bonds
is greater than the energy released from
forming new bonds
high
low
Rate of
reaction
Letter
fast
A
slow
B
fast
C
slow
D
fast
E
slow
F
fast
G
slow
H
Letter ...................
(1)
Page 54 of 141
(c)
The structure of silicon is similar to the structure of diamond.
Describe the structure of silicon and explain why it has a high melting point. You may draw
a diagram if this helps.
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(4)
(Total 15 marks)
Q43.
Millions of years ago the Earth formed as a giant ball of molten rock. The outer surface
cooled forming a thin, solid outer crust. Volcanic activity on the surface produced an atmosphere
containing the compounds carbon dioxide, ammonia, methane and water vapour.
Describe the bonding in any one of these compounds. You must include electronic structures in
your explanation.
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(Total 4 marks)
Page 55 of 141
Q44.
Uranium metal can be produced by reacting uranium hexafluoride with calcium.
UF6 + 3Ca → 3CaF2 + U
(a)
Describe how calcium and fluorine bond together to form calcium fluoride. The electron
arrangement of each atom is shown.
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(5)
(b)
Uranium has two main isotopes,
meant by the word isotope.
and
. Use these as examples to explain what is
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(4)
Page 56 of 141
(c)
At the start of a reaction there was 174.5 g of uranium hexafluoride, UF6.
Relative atomic masses: F 19; U 235
(i)
Calculate the relative formula mass of uranium hexafluoride, UF6.
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Relative formula mass UF6 = .................................... g
(1)
(ii)
Calculate the mass of uranium that would be produced from 134.5 g of uranium
hexafluoride.
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Mass of uranium = .................................. g
(2)
(Total 12 marks)
Q45.
Sodium reacts with chlorine to form the compound sodium chloride.
2Na + Cl2 → 2NaCl
Describe, in terms of electron arrangement, the type of bonding in:
(i)
a molecule of chlorine;
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(3)
Page 57 of 141
(ii)
the compound sodium chloride.
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(4)
(Total 7 marks)
Q46.
Brine, a solution containing sodium chloride in water, can be used to manufacture chlorine,
hydrogen and sodium hydroxide. A student sets up a simplified model of the industrial cell.
(a)
The electron arrangements of some atoms are shown here.
H
1
O
2.6
Na
2.8.1
C1
2.8.7
Page 58 of 141
(i)
Use the relevant electron arrangements to describe the bonding in water.
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(2)
(ii)
Use the relevant electron arrangements to describe the bonding in sodium chloride.
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(3)
(b)
Use the atomic structures of
and
to explain the meaning of the term isotopes.
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(3)
(Total 8 marks)
Q47.
Fluorine is a very useful element. It is placed in group 7 of the Periodic Table.
Use your knowledge of the elements in group 7 to help you answer these questions. You may
find that information in the Data Sheet may help you with this question.
(a)
Name another element in group 7 of the Periodic Table.
.....................................................................................................................................
(1)
Page 59 of 141
(b)
Cylinders filled with fluorine molecules are commercially available. What would you expect
the formula of a fluorine molecule to be?
.....................................................................................................................................
(1)
(c)
Fluoride ions are added to drinking water to help prevent tooth decay. What is the charge
on fluoride ions in the water?
.....................................................................................................................................
(1)
(d)
Fluorine reacts with the non-metal sulphur to make sulphur hexafluoride (SF6).
(i)
What type of bonding would you expect in sulphur hexafluoride?
..........................................................................................................................
(1)
(ii)
Explain the reason for your answer to part (i).
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(1)
(Total 5 marks)
Q48.
Silicon is an extremely important element. More than a million tonnes of silicon are
produced each year. Silicon is made by reducing silicon oxide (sand) with carbon (coke).
(a)
(i)
Complete the diagram below to show the arrangement of electrons in an atom of
silicon. The Data Sheet may help you with this question.
(2)
(ii)
Which electrons in the silicon atom take part in chemical reactions with other atoms?
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(1)
Page 60 of 141
(iii)
What features of all the atoms of the elements in group 4 of the Periodic Table might
give them similar chemical properties?
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(1)
(b)
Silicon is difficult to classify as a metal or a non-metal because it has properties which
resemble both. Some of the properties of silicon are listed below.
•
•
•
•
•
•
•
•
Silicon is a shiny blue/grey solid.
Silicon is placed in Group 4 of the Periodic Table.
Silicon has a relative atomic mass of 28.
Silicon has a very high melting point (1410ºC).
Silicon has a very high boiling point (2355ºC).
Silicon conducts electricity.
Silicon oxide will neutralise alkalis.
Silicon forms compounds in which the silicon atoms are bonded to other atoms by
covalent bonds.
(i)
Select two properties from the list above in which silicon resembles a metal.
1. .....................................................................................................................
2. .....................................................................................................................
(2)
(ii)
Select two properties from the list above in which silicon resembles a non-metal.
1. .....................................................................................................................
2. .....................................................................................................................
(2)
(Total 8 marks)
Q49.
The hydrogen halides (hydrogen fluoride, hydrogen chloride, hydrogen bromide and
hydrogen iodide) are important chemicals.
The diagram below represents a molecule of hydrogen chloride.
(i)
What type of particles are represented by the crosses (X)?
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(1)
Page 61 of 141
(ii)
What type of chemical bond holds the atoms in this molecule together?
.....................................................................................................................................
(1)
(iii)
Would you expect hydrogen chloride to be a gas, a liquid or a solid, at room temperature
and pressure? Explain your answer.
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(3)
(Total 5 marks)
Q50.
The extract below was taken from a leaflet on the uses of platinum. One of the uses
described was in making electrodes for spark plugs in car engines. The spark plug produces the
spark which ignites the fuel in the engine.
Spark Plugs
The electrodes in a spark plug have to conduct electricity very well. Since they
project into the combustion chamber of the engine, they must also be able to
withstand extremely high temperatures in a very corrosive atmosphere.
Nickel-based plugs have been produced for many years. They only last a fairly
short time. As the electrodes wear, combustion becomes less efficient and the
petrol is not burnt completely.
Platinum and other precious metals can now be used in spark plugs. These last
much longer and are more efficient. This can help to reduce air pollution.
The table below gives some information about platinum and nickel.
(a)
MELTING
POINT
(° C)
BOILING
POINT
(° C)
POSITION IN
REACTIVITY
SERIES
COST
(£/kg)
nickel
1455
2920
Higher than gold
2.5
platinum
1769
4107
below gold
6110
Compare nickel and platinum for use in making the electrodes in spark plugs.
A good answer should give advantages and disadvantages of each metal linking these to
the properties of the metals. Marks will be given for the way in which you organise
your answer.
You will need a sheet of lined paper.
(8)
Page 62 of 141
(b)
(i)
Describe the structure and bonding in metals.
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(3)
(ii)
Explain why metals such as nickel and platinum are good conductors of electricity.
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(2)
(Total 13 marks)
Q51.
(a) The electronic structure of a sodium atom can be written 2,8,1.
Write the electronic structure of a potassium atom in the same way.
.....................................................................................................................................
(1)
(b)
The electronic structure of a sodium atom can also be represented as in the
diagram below.
Page 63 of 141
(i)
Draw a similar diagram for a fluorine atom.
(ii)
Draw similar diagrams to show the electronic structure of the particles in
sodium fluoride.
(4)
(Total 5 marks)
Q52.
The following passage was taken from a chemistry textbook.
Germanium is a white, shiny, brittle element. It is used in the electronics industry because it is
able to conduct a small amount of electricity.
It is made from germanium oxide obtained from flue dusts of zinc and lead smelters.
The impure germanium oxide from the flue dusts is changed into germanium by the process
outlined below.
STEP 1
The germanium oxide is reacted with hydrochloric acid to make germanium
tetrachloride. This is a volatile liquid in which the germanium and chlorine
atoms are joined by covalent bonds.
STEP 2
The germanium tetrachloride is distilled off from the mixture.
STEP 3
The germanium tetrachloride is added to an excess of water to produce
germanium oxide and hydrochloric acid.
STEPS 1 to 3
are repeated several times.
STEP 4
The pure germanium oxide is reduced by hydrogen to form germanium.
(a)
Balance the equation below which represents the reaction in step 1.
GeO2 + ............ HCl →
GeCl 4
+
............ H2O
(1)
Page 64 of 141
(b)
Write a word equation for the reaction in step 3.
.....................................................................................................................................
(1)
(c)
Suggest why steps 1 to 3 are repeated several times.
.....................................................................................................................................
.....................................................................................................................................
(1)
(d)
The equation which represents the reaction in step 4 is shown below.
GeO2
(i)
+
2H2 →
Ge + 2H 2O
Explain what is meant by the term ‘reduced’.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Calculate the mass of germanium which could be made from 525 g of germanium
oxide. (Relative atomic masses: Ge = 73; O = 16).
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
Mass ......................................... g
(3)
(e)
Germanium is difficult to classify as either a metal or a non-metal.
(i)
Give as much evidence as you can from the information in this question to support
the view that germanium is a metal. Explain your answer as fully as you can.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
Page 65 of 141
(ii)
Give as much evidence as you can from the information in this question to support
the view that germanium is a non-metal. Explain your answer as fully as you can.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 13 marks)
Q53.
Diesel oil is obtained from crude oil. It can be used as a fuel for car engines. The diagram
below represents a compound found in diesel oil.
(a)
What is the formula of this compound?
.....................................................................................................................................
(1)
(b)
Each of the lines on the diagram above represents a covalent bond.
What is a covalent bond?
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
##
Sando-K is a medicine. It is given to people whose bodies contain too little of a particular element.
Sando-K is a mixture of two compounds. The formulae of the two compounds are given below.
KHCO3
(a)
KC1
Which metal do people given Sando-K need?
.....................................................................................................................................
(1)
(b)
Sando-K contains the ion, CO32–. Which gas would be produced if a dilute acid was added to
Sando-K? (The Data Sheet may help you to answer this question.)
.....................................................................................................................................
(1)
Page 66 of 141
(c)
The compounds in Sando-K contain ions.
Complete the two sentences below.
Atoms change into positive ions by ....................................... one or more
............................................................. .
Atoms change into negative ions by ......................................... one or
more .................................................... .
(4)
(d)
Electricity can be used to show that an aqueous solution of Sando-K contains ions.
(i)
Draw a diagram of an apparatus that you could use to prove that Sando-K
contains ions.
(4)
(ii)
Explain, as fully as you can, what would happen when the electricity is switched on.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 13 marks)
Q55.
Sulphur hexafluoride is a colourless, odourless, non-flammable gas, which is insoluble in
water and extremely unreactive. It is used as an insulator in high voltage transformers and
switchgear.
The diagram below represents a molecule of sulphur hexafluoride.
Page 67 of 141
(a)
What type of chemical bond holds the sulphur and fluorine atoms together in sulphur
hexafluoride molecules?
.....................................................................................................................................
(1)
(b)
Explain why sulphur hexafluoride has a low boiling point.
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
Explain how three of the properties of sulphur hexafluoride make it suitable for use as an
insulator inside electrical transformers.
Property 1: ..................................................................................................................
Explanation: ...............................................................................................................
.....................................................................................................................................
Property 2: ..................................................................................................................
Explanation: ...............................................................................................................
.....................................................................................................................................
Property 3: ..................................................................................................................
Explanation: ...............................................................................................................
.....................................................................................................................................
(3)
(Total 6 marks)
Q56.
Iron is used (as steel) to make the body panels for cars.
The iron panels have to be bendable so that they can be pressed into the shape required, but
must also be strong. The panels must also be able to conduct electricity because they form part
of the electrical circuits of the car.
Page 68 of 141
(a)
Iron is a typical metal. Describe the structure and bonding in a metal such as iron. You
may use a diagram if you wish.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(b)
Explain how the structure and bonding of iron:
(i)
allows the body panels to conduct electricity;
...........................................................................................................................
(2)
(ii)
allows the body panels to be bent into shape;
...........................................................................................................................
(1)
(iii)
gives the body panels strength.
...........................................................................................................................
(1)
(Total 8 marks)
Q57.
The diagram represents the structure of graphite.
Page 69 of 141
Use your knowledge and understanding of the structure of graphite to explain why graphite
can be used:
(a)
in the ‘leads’ of pencils;
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(b)
as an electrical conductor.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(Total 5 marks)
Page 70 of 141
Q58.
The diagram shows a model of part of the giant lattice of a metal.
(a)
Name particles X and Y.
X .....................................................
Y .....................................................
(2)
(b)
Explain, in terms of the giant structure above, why is it possible to bend a piece of metal.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Page 71 of 141
Q59.
The diagram shows the structure of diamond.
(a)
To gain full marks for this question you should write your ideas in good English. Put them
into a sensible order and use the correct scientific words.
Explain, as fully as you can, why diamond has a high melting point.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
Page 72 of 141
(b)
The diagram below shows the outer electron shells of five carbon atoms in the giant lattice
of diamond.
Carbon atom C forms bonds with each of the carbon atoms W, X, Y and Z.
Draw the positions of all the electrons in the outer shells of each of carbon atoms C, W, X,
Y and Z.
(3)
(Total 6 marks)
Q60.
(i)
Complete the drawing to show the electron structure of a hydrogen fluoride molecule.
Draw electrons as dots or crosses.
(1)
Page 73 of 141
(ii)
Explain why hydrogen fluoride is a gas at room temperature.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
##
In this question you will need to use the following information:
Relative atomic masses: H 1; O 16; Mg 24.
The volume of one mole of any gas is 24 dm3 at room
temperature and atmospheric pressure.
The diagram shows a chemical reaction taking place in a conical flask.
The balanced equation for this reaction is:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
(a)
Write a balanced ionic equation for this reaction.
....................................................................................................................................
(2)
(b)
Calculate the mass of magnesium required to produce 0.50 g of hydrogen. Show clearly
how you work out your final answer and give the unit.
.....................................................................................................................................
.....................................................................................................................................
Mass = ...............................
(2)
Page 74 of 141
(c)
(i)
Draw a diagram to show how the electrons are arranged in a hydrogen molecule.
(1)
(ii)
What is the name of the type of chemical bond between the hydrogen atoms in a
hydrogen molecule?
...........................................................................................................................
(1)
(d)
The chemical formula for hydrogen peroxide is H2O2.
Calculate, to the nearest whole number, the percentage, by mass, of hydrogen in
hydrogen peroxide. Show clearly how you work out your answer.
....................................................................................................................................
....................................................................................................................................
Percentage = ................................. %
(2)
(Total 8 marks)
Q62.
(a)
The diagram shows part of the ionic lattice of a sodium chloride crystal.
Page 75 of 141
(i)
Complete the spaces in the table to give information about both of the ions in this
lattice.
Name of ion
Charge
.....................................................
.....................................................
.....................................................
.....................................................
(2)
(ii)
When it is solid, sodium chloride will not conduct electricity. However, molten sodium
chloride will conduct electricity. Explain this difference.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(iii)
Complete the sentence.
Sodium chloride conducts electricity when it is molten and when it is
..........................................................................................................................
(1)
(b)
The symbol for a calcium atom can be shown like this:
(i)
What is the mass number of this atom?
..........................................................................................................................
(1)
(ii)
What information is given by the mass number?
..........................................................................................................................
..........................................................................................................................
(1)
(c)
Calcium burns in oxygen with a brick-red flame. The product is a white solid. It is calcium
oxide and its formula is CaO.
(i)
Balance the chemical equation for the reaction.
Ca(s) + O2(g) → CaO(s)
(1)
Page 76 of 141
(ii)
Describe, in terms of electrons, what happens to a calcium atom when it becomes a
calcium ion.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(Total 10 marks)
Q63.
Chlorine will combine with the non-metal element, carbon, to form this molecular
compound.
(a)
What is the type of bond in this molecule?
.....................................................................................................................................
(1)
(b)
Explain how these bonds are formed. (You may use a diagram).
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
Page 77 of 141
Q64.
(a) By reference to their structure, explain how the particles in a piece of metal are held
together and how the shape of the metal can be changed without it breaking.
(You may use a diagram in your answer.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(b)
Explain why metals are good conductors of electricity and suggest why this conductivity
increases across the periodic table from sodium to magnesium to aluminium.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 9 marks)
Page 78 of 141
Q65.
Sodium carbonate reacts with acids.
(i)
Complete the word equation.
sodium carbonate + hydrochloric acid → sodium chloride + ...................... + water
(1)
(ii)
Name the salt produced if sodium carbonate reacts with dilute nitric acid.
...........................................................................................................................
(1)
(Total 2 marks)
Q66.
The questions which follow refer to the element hydrogen.
(a)
Draw a diagram to show the bonding in one molecule of hydrogen.
(2)
Page 79 of 141
(b)
The table gives information about two compounds which contain hydrogen.
Use the information in the table to explain why it is difficult to classify hydrogen as a metal
or a non metal.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 6 marks)
Q67.
(a)
Balance these chemical equations.
(i)
H2 +
O2 →
H 2O
(1)
(ii)
Al +
O2 →
Al 2O3
(1)
(b)
Briefly explain why an unbalanced chemical equation cannot fully describe a reaction.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 80 of 141
(c)
Explain, as fully as you can, why a water molecule contains two hydrogen atoms but a
hydrogen chloride molecule contains only one.
(You may use a diagram in your answer if you wish).
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 7 marks)
Q68.
The diagram shows the elements in Group 4 of the periodic table.
Page 81 of 141
Carbon is a non-metal and silicon is usually considered to be a non-metal.
Tin and lead have all the usual properties of metals.
Germanium has these properties:
•
grey-white shiny solid
•
melting point 937°C
•
semi-conductor
•
reacts with chlorine to form the chloride (GeCl4) which is a liquid
molecular compound
•
(a)
germanium oxide reacts with acids to form a salt solution and water. It also reacts
with alkalis.
With reference to their structure, explain why tin and lead are good conductors
of electricity.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(b)
Would you classify germanium as a metal or as a non-metal? Give your reasons.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 6 marks)
Page 82 of 141
Q69.
The diagrams show the giant structures of sodium chloride and diamond.
sodium chloride (melting point 801°C)
(a)
diamond (melting point 4800°C)
The equation shows how sodium choride could be formed.
Balance the equation.
Na
+
Cl2
→
Na Cl
(1)
(b)
By reference to the detailed structure of sodium chloride explain fully why:
(i)
sodium chloride has a quite high melting point,
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
solid sodium chloride melts when it is heated strongly,
...........................................................................................................................
...........................................................................................................................
(2)
(iii)
molten sodium chloride will conduct electricity.
...........................................................................................................................
...........................................................................................................................
(1)
Page 83 of 141
(c)
By reference to the detailed structure of diamond, explain why the melting point of
diamond, is higher than that of sodium chloride.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 7 marks)
Q70.
(a)
The diagrams represent the atomic structures of two gases, hydrogen and helium.
Hydrogen gas is made up of diatomic molecules (molecules with two atoms).
Helium gas exists as single atoms.
(i)
How is a molecule of hydrogen formed from two hydrogen atoms?
(You may use a diagram as part of your answer)
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
Why does helium exist only as single atoms?
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
Page 84 of 141
(b)
Hydrogen combines with carbon to form methane.
Each molecule contains four hydrogen atoms strongly bonded to a carbon atom.
Explain why methane has a low boiling point.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
Q71.
(a) Copper is a metal.
Explain how it conducts electricity.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 85 of 141
(b)
Graphite is a non-metal.
Use the information to explain why graphite conducts electricity.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 5 marks)
Page 86 of 141
M1.
(a)
lithium = Li
(ignore mass / atomic numbers)
fluorine = F (do not allow if case is incorrect)
for 1 mark each
2
(b)
(allow ● or o for electrons)
(allow any positions for the seven electrons added provided
they are on the outer ring)
for 1 mark
1
(c)
(2,8)+ or (2,7)–
(brackets not required) gains 1 mark
but (2,8)–
gains 2 marks
2
[5]
M2.
(a)
positive / + / 2
gains 1 mark
but 2+ / ++ / +2
gains 2 marks
2
(b)
Ideas that: 2
Ca2+
Br- [Do not disqualify for "bromine" ions]
Ions / They are in the ratio 1:2
any two for 1 mark each
2
[4]
M3.
(a)
Calcium
No of protons
Fluorine
15
No of neutrons
No of electrons
Phosphorus
10
20
for 1 mark each
3
Page 87 of 141
(b)
(i)
gain of electron(s)
from (atoms) (of) calcium
for 1 mark
2
(ii)
Ca+
gains 1 mark
but superscript only Ca2+ / Ca ++
gains 2 marks
2
(c)
atoms
electrons
molecule(s)
not compound
each for 1 mark
3
(d)
(i)
ideas that
•
ionic – strong forces between ions
•
molecular – weak forces between molecules
each for 1 mark
2
(ii)
ideas that
•
ionic – ions/charged particles are free to move
•
molecular -molecules do not carry a charge
each for 1 mark
2
[14]
M4.
(a)
(i)
A calcium hydroxide/limewater/Ca(OH)2 not CaOH
(ii)
B calcium oxide/Quicklime/CaO
(iii)
C hydrogen/H2 (accept correct formulae)/ not H2/H
each for 1 mark
3
(b)
(i)
idea that
electrons are lost (by the calcium atom)
gains1 mark
but two electrons are lost (by the calcium atom)/lose outer electrons to get full shell
gains 2 marks
calcium ions are 2+
for 1 mark
Page 88 of 141
(ii)
electrons are gained (by the oxygen atom)
gains 1 mark
but two electrons are gained (by the oxygen atom)/gain electrons to get full outer
shell
gains 2 marks
oxygen ions are 2–
for 1 mark
6
(b)
(c)
(i)(ii) needs:
electron loss/gain
number (2)
charge (+/–)
idea that
they are held together by many/strong forces/bonds
a lot of energy/high temperature is required to break these forces/bonds
each for 1 mark
2
[11]
##
(a)
positive
for 1 mark
1
(b)
any reference to loss of electrons
for 1 mark
reference to charge being +2 (in (a)) or to loss of 2 electrons (in (b))
for 1 mark
2
[3]
Page 89 of 141
M6.
(a)
This part was not marked
1
(b)
electrolysis
1
because calcium is more reactive (than aluminium or carbon)
accept it is more reactive
or very reactive
1
OR
in a blast furnace
1
because calcium is less reactive (than carbon or lower)
1
(c)
any equation from
1 mark for correct formulae
1 mark for balancing
2ZnO + C → 2Zn + CO2
ZnO + CO → Zn + CO2
ZnO + C → Zn + CO
1
[5]
M7.
(a)
(i)
ammonia and hydrogen chloride
both required either order
accept formulae if correct in every detail
1
(ii)
ammonium chloride / NH4Cl
do not credit ammonia chloride
1
(iii)
the fumes / gases / are poisonous / toxic
or ammonia and hydrogen chloride are
poisonous / toxic / lethal
accept just ammonia is poisonous / toxic
accept just hydrogen chloride is
poisonous / toxic
accept vapour is poisonous / toxic
do not credit just fumes are dangerous
or harmful
1
Page 90 of 141
(iv)
nitrogen
do not credit N/N2
1
hydrogen
do not credit H/H2
1
molecule
do not credit compound or mole
1
covalent
accept single / molecular
1
(b)
(i)
proton
neutron
electron
either all three correct
or one or two correct
however do not credit a response
which is repeated
2
(ii)
protons and neutrons
both required in either order
1
[10]
M8.
(a)
(i)
rings of 2, 8 and 3 electrons
credit 2, 8, 3 pay particular attention to the outer shell in diagrams
1
(ii)
rings of 2, 8 and 7 electrons
credit 2, 8, 7 pay particular attention to the outer shell in diagrams
1
Page 91 of 141
(b)
(i)
labels not required on atoms
charges need to be shown on ions
reference to outer shell is required otherwise a maximum of two
marks
structure of atoms/ions marks
(ring of 2, 8, 1 for sodium) or the outer shell of sodium only contains 1 electron
credit 2, 8, 1 or an ion 2, 8 or two circles and 1 electron in outer
shell
1
(ring of 2, 6 for oxygen) or outer shell only contains 6 electrons
credit 2, 6 or an ion 2, 8 or two circles
1
transfer of electrons mark
two sodiums needed to supply two outer electrons to oxygen to complete
the (one oxygen's) outer shell
award maximum of two marks if a covalent structure is given
credit two rings of electrons for sodium showing outer electrons
transferring to outer shell of one oxygen for three marks
do not accept diagrams showing overlapping rings for third mark
1
(ii)
loses an electron
credit atoms lose electrons or oxygen takes the electron ignore oil
rig
1
[6]
M9.
NOTE
In this question and throughout the Paper, if the name of a chemical is
asked for, then the formula is acceptable only if it is correct in every detail.
If the name is correct and the candidate has tried to be ‘helpful’ by giving,
in addition, an incorrect version of the formula, then this is acceptable
provided it does not lead to ambiguity.
(i)
nitric (acid)
accept HN03
1
(ii)
sulphuric (acid)
accept H2SO4
1
Page 92 of 141
(iii)
heat given out
or temperature rise
or energy given out
or steam
do not credit just ‘use a thermometer’
do not credit just 'change in temperature'
1
(iv)
neutralisation
accept neutralise
accept neutral
accept formation of salt or water
do not credit exothermic
1
[4]
M10.
(a)
both correct in each row
electron ...– (1)
allow negative
1
1 .......... 0
allow neutral or none
1
proton .....+ (1)
allow positive
1
(b)
(i)
protons...electrons
both correct in correct order
1
(ii)
protons....neutrons
both correct in either order
1
(c)
(i)
sodium fluoride
do not credit sodium fluorine
1
NaF
must be correct in every detail
do not credit NAF and the like
1
Page 93 of 141
(ii)
ionic
accept ion (bonding)
do not credit ironic or iron (bonding)
1
(iii)
electron transferred from sodium to fluorine
accept electron transferred from metal to non-metal
either positive sodium ion and negative fluoride ion
or correctly identified by the symbols Na+ and F- accept ‘positive
sodium ion and negative fluorine ion’
1
or attracted because have opposite charge(s)
or (atoms/ions) form an (ionic) lattice or (atoms/ions) form a
crystal
e.g.
or both marks may be gained by a suitable dot and cross diagram
1
[10]
M11.
(a)
proton + (1)
both required
neutron 1
both required
electron – (1)
both required
3
(b)
2.8.3
accept words or diagram to this effect
1
(c)
(i)
24
1
(ii)
52
1
(d)
any one of
•
gains one or more electrons
accept gains an electron
•
becomes an anion
do not credit becomes an ion
•
becomes a negative ion
1
Page 94 of 141
(e)
sodium ions have a (single) positive
charge and chloride ions have a
(single) negative charge
do not credit ‘chlorine ions’ but
allow this error to be carried forward
1
ions with opposite charge are
attracted (to each other)
or the positive ions and the negative ions are attracted (to each
other)
or the sodium ions and the chloride ions are attracted (to each
other)
1
(positive and negative) ions are
arranged alternatively (in each
direction or dimension)
or ions with the same charge are repelled (by each other) no mark
for just ionic bonds
1
[10]
M12.
(a)
LHS lithium + water
accept Li and H2O
accept hydrogen oxide for water
1
RHS hydrogen + lithium hydroxide
accept H2 and LiOH
ignore attempts at balancing
ignore charges
1
(b)
Quality of written communication
One mark for the correct use of any
three of the terms atom, covalent,
bond(ing), saturated, hydrocarbon
or alkane
1
Page 95 of 141
any three from:
one / the carbon (atom)
reject molecules once
four hydrogen (atoms)
shape / properties neutral
CH4
hydrocarbon
saturated / single bond
covalent bond / shared electrons
alkane
reject ionic bond
3
[6]
M13.
8 electrons in outer shell
accept anywhere in outer shell
accept dots or crosses
1
negative sign outside bracket
1
[2]
M14.
(i)
B or 2, 8, 1
for one mark
1
(ii)
A or 2, 8
for one mark
1
[2]
M15.
(a)
Group 2 / Alkaline Earth Metals
for 1 mark
1
Page 96 of 141
(b)
(i)
MgCl2/Mg2+ (Cl–)2
(or equation with correct answer)
for 1 mark
1
(ii)
ionic / electrovalent
for 1 mark
1
[3]
M16.
(a)
2 2 multiples of ½ allowed
for 1 mark
1
(b)
(i)
2. 8. 1 and 2. 8. 7
gains 3 marks
1 mark for 2 electrons in each inner shell
1 mark for 8 electrons in each second shell
1 mark for 1 electron in sodium outer shell
and 7 in chlorine outer shell
3
(ii)
sodium atom loses;
electron;
chlorine atom gains;
electron
for 1 mark each
inversion = 2 marks
lose negative charge = 1 mark
4
(c)
(i)
KCl (accept 2KCl)
for 1 mark
1
(ii)
both have on electron in outer shell/same number of electrons/
lose same number of electrons in compound formation/
both lose one electron
for 1 mark
1
(d)
0 amps;
the ions;
cannot move in the solid
solid Na chloride does not conduct
for 1 mark each
3
(e)
(i)
water (H2O)
for 1 mark
1
Page 97 of 141
(ii)
(1) chlorine;
(2) hydrogen
for 1 mark
1
[15]
M17.
(a)
(i)
H2SO4 or red (acidic) pH < 7
accept names of compounds
accept correct use of acidic
1
NaOH or purple (alkaline) pH > 7
alkaline and neutral without any mention of pH for 1 mark only
1
NaCl or green (neutral) pH 7
ignore high or low pH
1
(ii)
hydrogen (ion)
accept proton
accept hydroxonium ion
1
H+
accept H3O+ for hydroxonium ion
1
(b)
(i)
neutralisation
1
(ii)
NaOH + HCl
ignore state symbols
1
NaCl + H2O
ignore state symbols
maximum of 1 mark if incorrectly balanced
1
(c)
(i)
sodium – 2 . 8 . 1
accept 2.8.1 written
1
chlorine – 2 . 8 . 7
accept 2.8.7 written
1
(ii)
ion(s)
1
Page 98 of 141
(iii)
attraction between oppositely charged particles (ions)
accept attraction between + and – particles (ions)
accept electrostatic attraction
1
(d)
chloride ions lose electrons to form chlorine
Cl– – e– → Cl
1
hydrogen ions gain electrons to form hydrogen
H+ + e– → H
1
sodium hydroxide remains in solution
Na + and OH– remain in solution to form sodium hydroxide
1
[15]
M18.
(a)
all electrons correct (inner shell need not be shown)
three bond pairs and two electrons anywhere else
can use dots, crosses or e’s in any combination
1
(b)
covalent
accept phonetic spelling
do not accept convalent
1
[2]
M20.
(a)
bonding pair in the overlap and 6 other electrons arranged around the chlorine
must have either circles or symbols
need not be pairs but must not be in the overlap region
accept without H and Cl if clear
accept all x’s or all o’s
1
Page 99 of 141
(b)
H2
+
Cl2
→
2HCl
accept multiples or fractions
accept correct formulae but not balanced for 1 mark
correctly balanced equation containing
‘correct’ lower / upper case symbols gets 1 mark
2
(c)
MgCl2
accept Mg2+(Cl-)2
1
(d)
because magnesium chloride is made of ions or is ionic
accept there are strong forces of attraction between the ions /
particles in MgCl2 or strong electrostatic attractions
accept more energy to separate particles in MgCl2
do not accept MgCl2 molecules
do not accept reference to breaking bonds
1
hydrogen chloride is made of molecules or is covalent
accept there are only weak forces of attraction (between the
particles / molecules) in HCl
do not accept weak covalent bonds
do not accept reference to breaking bonds
do not accept MgCl2 is a solid and HCl is a gas
1
[6]
M21.
(a)
157
correct answer with or without working
(2 × 19 + 119) for 1 mark only
allow (119 + 19 =) 138 for 1 mark only
ignore units
2
(b)
24.2
accept answers in the range 24 to 24.2038.....
ignore incorrect rounding after correct answer
25 only without working gains 1 mark or
38/157 × 100 gains 1 mark or
(19/157 × 100 =) 12 to 12.1 gains 1 mark
allow error carried forward from part(a)
38/(a) × 100 gains 2 marks if calculated correctly
(19/138 × 100 =) 13.8 gains 1 mark
2
Page 100 of 141
(c)
0.29
accept answers in the range 0.28 to 0.3
allow error carried forward from part (b)
(b)/100 × 1.2 correctly calculated
ignore units
1
(d)
an electron
allow electrons
allow electron shared / lost for 1 mark
apply list principle for additional particles
1
is gained owtte
must be linked to electron
accept can hold / take in if in correct context
eg it can hold another electron (in its outer shell) = 2 marks
it can take an electron (from another atom) = 2 marks
ignore reference to fluoride ions
incorrect number of electrons gained does not gain the second
mark
1
[7]
M22.
(a)
electric current / electricity
1
plus one from:
•
is passed through ionic compound / substance / electrolyte
•
passed through molten/aqueous compound / substance
must be linked to electricity
allow liquid compound / substance
do not allow solution / liquid alone
•
causing decomposition
accept split up / breakdown / breaking up owtte
ignore separated
accept elements are formed
ignore new substances form
1
(b)
hydrogen
accept H2
do not accept H / H2
1
Page 101 of 141
(c)
one electron from each atom
accept each carbon is bonded to three other carbon atoms leaving
one (unbonded) electron owtte
1
is delocalised / free (to move)
must be linked to electrons
answers of delocalised / free electrons only, gains 1 mark
accept each carbon is bonded to three other carbon atoms leaving
delocalised / free electrons = 2 marks
maximum 1 mark if graphite described as a metal / giant ionic
lattice
1
[5]
M23.
(a)
any one from:
•
they are made of layers
do not accept line / rows / lattice
•
atoms / ions / particles / layers (of atoms) can slide over each other
1
(b)
any one from:
•
smaller / tiny or very small
do not allow small alone
•
correct size range 1 to 100 nanometres
•
a few hundred atoms in size
if they state smaller and give a size outside range ignore size if it is
less than 20,000
1
Page 102 of 141
(c)
harder
1
plus one from:
•
so does not wear as quickly / erode as quickly
ignore corrode
•
less vulnerable to damage owtte
harder to wear down = 1 mark
•
because they have a high surface area to volume ratio
or
stronger (1)
plus one from: (1)
•
less likely to break / do not break
accept withstand pressure
•
not as vulnerable to damage owtte
harder and stronger alone gains 1 mark
•
do not bend out of shape
•
because they have a high surface area to volume ratio
1
[4]
M24.
(a)
(i)
or
1
allow any arrangement of electrons on the shells
accept o, x, - or e as representing electrons
(ii)
nucleus
accept nucleus (protons plus neutrons)
do not accept protons plus neutrons on its own
allow nuclei / nucles / neucleus / phonetic spelling
do not accept neutron
1
Page 103 of 141
(b)
it has 2 more neutrons or converse
accept ‘it has more neutrons’ or ‘different number of neutrons’ for 1
mark
‘2 more protons / electrons + correct number of neutrons’ = max 1
mark
or
O-16 has 8 neutrons (1 mark)(*)
O-18 has 10 neutrons (1 mark)(*)
(*)if incorrectly calculated but shows more neutrons in 0-18 allow
for 1 mark
accept it has more particles
or
it has 2 more particles for 1 mark
ignore any reference to charges
just 2 more without reference to particles = 0 marks
2
[4]
M25.
(a)
Stops / reduces air from escaping (owtte)
allow keeping shape or keeping it hard
1
(b)
a layer a few hundred atoms thick
1
(c)
any two from:
•
last longer
•
use fewer balls
•
less materials or save resources
•
less manufactured
accept less factories
•
less energy
•
less fuel
•
less pollution / greenhouse effect / global warming
•
less waste
ignore references to cost / recycling
any two ideas
2
[4]
Page 104 of 141
M26.
(a)
1-100 nm in size
or
a few (hundred) atoms in size
accept very / really small / tiny
or 10–9
accept billionth of a metre or any number that implies very small
accept measured in nanometers
if answer ‘very small’ ignore incorrect numerical values
1
(b)
any two from:
•
less tennis balls need to be made
•
tennis balls last longer or don’t have to replace as often
•
less materials / resources / fuel used up / saves resources
accept saving materials
•
less energy used or making tennis balls uses energy
accept saving energy
•
less pollution caused
accept named pollutant
accept global warming / greenhouse effect
•
less waste
eg fewer tennis balls going to landfill
2
[3]
M27.
(a)
(i)
increase (owtte) or gets hotter
ignore gives out heat / takes in heat
1
Page 105 of 141
(ii)
any two from:
•
bonds are strong
accept hard to break
•
a lot of energy needed to break bonds
allow heat for energy
•
all atoms are joined by (covalent bonds
accept forms lattice
•
a large number of bonds would need to be broken
reference to ionic / metallic = 1 mark
intermolecular forces /forces between molecules = max 1 mark
ignore electrostatic
many strong bonds need to be broken = 2 marks
accept ‘double bonds’ as equivalent to bonds
2
(b)
any two from:
•
particles have more energy
ignore more vibrations
•
particles move faster
ignore move more
•
particles collide more often or
more collisions
accept answers such as hit / bump
•
more particles / particle collisions
have the activation energy
or
more of the particles / particle collisions have
enough energy to react
or
collisions are more energetic / harder (owtte)
or
more of the collisions are successful
if electrons rather than particles stated then max 1 mark
there are more collisions and more of the collisions are successful
= 2 marks
accept more collisions per second / unit of time for 2 marks
accept ‘more successful collisions’ for 1 mark
2
[5]
Page 106 of 141
M28.
(a) Marks awarded for this answer will be determined by the Quality
of Written Communication (QWC) as well as the standard of the
scientific response.
No relevant content.
0 marks
There is a brief description of the electrolysis of aluminium oxide.
Level 1 (1–2 marks)
There is some description of the electrolysis of aluminium oxide.
Level 2 (3–4 marks)
There is a clear, balanced and detailed description of the
electrolysis of aluminium oxide.
Level 3 (5–6 marks)
examples of the chemistry points made in the response
(b)
•
aluminium oxide is melted / made liquid
•
aluminium ions are attracted to the negative electrode
•
at the negative electrode aluminium is formed or
aluminium ions gain electrons
•
oxide ions are attracted to the positive electrode
•
oxygen is formed at the positive electrode or oxide
ions lose electrons
•
the oxygen reacts with carbon to make carbon dioxide or
carbon dioxide formed at positive electrode.
there are delocalised electrons / free electrons / electrons
which move within the aluminium / metallic structure
1
therefore these electrons are able to carry the current / charge
1
if the candidates use the terms covalent / ionic / molecules /
intermolecular incorrectly in the answer this will limit the mark to a
maximum of 1.
[8]
M29.
(a)
one nitrogen atom joined to three hydrogen atoms
1
correct pairs of electrons
1
Page 107 of 141
(b)
because ammonia is made of small molecules / simple
molecules / simple molecular structures
1
and so there are weak forces between the molecules
or and so the intermolecular forces are weak
1
incomplete answers that link only size of molecule or strength of
intermolecular forces with boiling point only gain 1 mark
(c)
(i)
hydroxide
1
(ii)
nitric
1
(d)
because this is an endothermic reaction
1
that takes in energy from the surroundings as the ammonium
nitrate dissolves
1
[8]
M30.
heat
1
then mould / extrude into a new shape / object
1
plastic made of polymer chains that can move (when heated)
1
because plastic / polymer has weak intermolecular forces
1
[4]
M31.
(a)
the sodium atom loses / transfers an / one electron
1
the chlorine atom gain(s) this / an / one electron
1
involves electrons in the outer energy levels / shells of
both the sodium atom and the chlorine atom
1
Page 108 of 141
(b)
sodium chloride has a giant structure / lattice of oppositely
charged ions / positive and negative ions
1
the electrostatic forces of attraction / bonds between ions
are strong
1
therefore sodium chloride has a high melting point because a
large amount of energy is needed to make the ions mobile
1
[6]
M32.
(a)
allow all dots
or
all crosses
or
combination
or
all e / e–
or –
or other suitable symbols
centre of symbols must be on or inside overlapping
areas within reason
1
(b)
(i)
any two from:
•
no change initially or stays constant at the beginning
•
increase
•
slowly at first and then more rapidly
accept converse arguments
allow vapour pressure is 0 at any temperature <–100oC for 1 mark
accept positive correlation
accept explanation based on kinetic theory eg particles have more
kinetic energy
allow reasonable attempt at using numbers
2
(ii)
–44 (using graph) accept –43 to –45
1
Page 109 of 141
(c)
•
intermolecular forces / bonds or forces / bonds between molecules
1
•
bonds / forces are weak
covalent bonds are weak = 0 marks
if they do not gain either of the marks on the left then allow simple
covalent / molecular / made of small molecules for 1 mark
1
[6]
M33.
(a)
2.61 / range 2.5 to 2.7
correct answer with or without or with wrong working gains 2 marks
(accept answers between 2.5 and 2.7)
if answer incorrect moles of salicylic acid = 2/138 = 0.0145 moles
ie 2/138 or 0.0145 gains 1 mark
or
(180/138) × 2 gains 1 mark
or
1 g → 180/138 = (1.304 g) gains 1 mark
(not 1.304g alone)
2
(b)
42.1 range 40.7 to 42.3
accept correct answer with or without or with wrong working for 2
marks
ecf ie (1.1 / their answer from (a)) × 100 correctly calculated gains
2 marks
if answer incorrect percentage yield = 1.1 / 2.61 × 100 gains 1
mark
if they do not have an answer to part (a)
or
they choose not to use their answer then:
•
yield = (1.1 / 2.5) × 100 (1)
•
= 44
accept 44 for 2 marks with no working
2
Page 110 of 141
(c)
any one from:
•
errors in weighing
•
some (of the aspirin) lost
do not allow ‘lost as a gas’
•
not all of the reactant may have been converted to product
eg reaction didn’t go to completion
allow loss of some reactants
•
the reaction is reversible
accept other products / chemicals
•
side reactions
ignore waste products
•
reactants impure
•
not heated for long enough
•
not hot enough for reaction to take place
1
(d)
any one from:
•
use lower temperature
•
use less fuel / energy
ignore references to use of catalyst
•
produce product faster or speed up reaction
•
more product produced in a given time (owtte)
•
increased productivity
•
lowers activation energy
1
[6]
Page 111 of 141
M34.
five ideas from the following for one mark each
•
each carbon / atom joined / bonded to three other carbon / atoms
or each carbon forms 3 bonds
•
in layers
•
only weak forces (of attraction) / bonds between layers
allow weak electrostatic / intermolecular forces /bonds between
layers
•
layers / atoms can slide over each other
•
one electron on each carbon is not used for bonding
•
electrons delocalised or electrons free
allow ‘sea’ of electrons
•
electrons carry the charge / current
•
giant structure / lattice
•
covalent (bonds)
•
strong bonds or a lot of energy needed to break bonds
reference to ionic bonding = max 4
diagrams could be used:
•
to show layered structure
•
to show that each carbon is bonded to three other
carbon atoms
•
to show giant structure (at least 3 rings required)
[5]
M35.
(a)
(i)
any one from:
•
they are positive / cations
•
they are H+
•
opposite charges attract
ignore atom
1
(ii)
potassium is more reactive (or reverse)
assume ‘it’ refers to hydrogen
allow potassium reacts with water
allow potassium is very reactive or most reactive metal / element
allow hydrogen gains electrons more easily / is reduced more
easily
accept potassium is higher up the reactivity series
1
Page 112 of 141
(b)
6 and 2
accept correct multiples and fractions
1
(c)
(i)
the reaction / it is reversible or a description of a reversible reaction
allow ‘it is an equilibrium’
allow reversible symbol drawn correctly
allow ‘the reverse / back reaction’
1
(ii)
lithium nitride
assume that ‘it’ or if they do not specify means lithium nitride
assume lithium / lithium nitrate refers to lithium nitride
•
hydrogen is bonded / held / absorbed / has formed a
compound / reacted with lithium nitride
1
plus one of:
•
does not explode / cause a fire
•
is not free / less hydrogen
•
is not under pressure
•
does not leak
•
is only released slowly
1
•
compound of hydrogen with lithium nitride / product is
(more) stable / less reactive / less chance of a reaction
accept converse for hydrogen as below
assume that gas / hydrogen means gas in the cylinder
•
hydrogen (in cylinder) / gas is not bonded / held
absorbed / in a compound / reacted with lithium
nitride
1
plus one of:
•
can explode / cause a fire
•
is free
•
is under pressure
•
can leak
•
releases quickly
1
(d)
(i)
loss of an electron or loses electrons
do not accept any ref. to oxygen
1
Page 113 of 141
(ii)
full outer shell of 8 electrons on circle
need not be paired
can be ×, dot or e
do not accept if extra electrons added to inner shell
1
[10]
M36.
(a)
C
0.60
H
0.15
O
0.40
1
12
1
= 0.05
= 0.15
16
= 0.025
1
2
6
1
1
C2H6O
1 mark for dividing the correct amount or multiples of correct
amount by Ar
1 mark for proportions
1 mark for whole number ratio – accept any multiple
1 mark for correctly written simplest formula
correct formula without working gets only 2 marks
correct formula gains full marks
provided steps 1 and 2 are correct.
ecf can be allowed from step 2 to 3 or step 3 to 4
formula can be in any order eg OH6C2
1
(b)
intermolecular forces / bonds
1
are weak
(covalent) bonds are weak = 0
or
forces between molecules or bonds between molecules (1)
(attractive) forces are weak = 1
are weak (1)
if no marks awarded, allow low boiling point or small Mr for 1 mark
1
Page 114 of 141
(c)
(i)
to check the safety of the perfume (owtte)
accept references to possible harmful / dangerous effects of
perfume or possible reactions on skin
eg to show it does not damage skin / cause cancer etc.
allow to see what it smells like on the skin
allow so the company do not have to test on animals
1
(ii)
any two from:
idea from text linked with an explanation
•
the company claim to have tested the product:
but we cannot be certain they have or how thorough they
are or how accurately reported
•
companies did not disclose how they did their tests:
so they could not be checked or so they could not be
shown to be reliable / valid or so they could not be repeated
or converse
eg companies should disclose how they did their tests so that
results can be checked etc.
•
companies may not have repeated their tests:
so they may not be reliable
•
companies do their own tests:
so they may be biased or so they may not be truthful about their results or so
they may not be reliable
or converse
eg independent tests should be done so as to ensure there is no
bias etc.
•
the companies are using different tests:
so the results cannot be compared or so results will be different or so results
will not be fair / valid / reliable
or converse
eg companies should do the same tests so that the results will be
fair etc.
•
companies would not give false information because of damage to reputation
or it might lead to litigation
2
[9]
M37.
(a)
2Mg + O2 → 2MgO
accept correct multiples / fractions
1
Page 115 of 141
(b)
electrons do not need to be paired
accept dots / circles / e instead of crosses
do not allow 2.6 without diagram
1
(c)
electrons do not need to be paired
allow without bracket s/ must have the charge
accept dots / circles / e instead of crosses
ignore extra empty outer shells
ignore nucleus
do not allow [2.8]2+ without diagram
1
(d)
oppositely charged (ions / atoms)
allow positive and negative(ions / atoms)
1
(they) attract
must be in correct context
accept held by electrostatic forces
ignore ionic bonding
maximum 1 if they refer to intermolecular forces / attractions /
covalent bonds
1
(e)
magnesium chloride
accept MgCl2 (if correctly written)
1
[6]
Page 116 of 141
M38.
any four points from:
•
high melting point owtte
ignore boiling point
•
many or all atoms joined together
•
each silicon (atom) joined to four oxygen (atoms) or each oxygen joined to two silicon
•
covalent (bonds)
•
many bonds would need to be broken
•
strong bonds
allow hard to break bonds
•
lot of energy / heat needed to break bonds
allow high temperature needed to break bonds
•
giant / macromolecular / lattice / diamond structure
•
unreactive
allow doesn’t react with materials within furnace = 1 mark
•
rigid / hard structure
•
no free electrons
•
poor conductor of heat
giant covalent structure = 2 marks
max 3 if ionic / metallic bonding mentioned
ignore electrostatic
ignore molecules / intermolecular forces
[4]
M39.
(a)
nanoparticles / they are small(er)
accept 1–100 nm or a few atoms in size
1
so can easily pass through pores / skin / cell / membranes / arteries / veins /
capillaries / into blood stream owtte
must be a comparative statement
can be inferred from smaller particles
allow absorbed for pass through
1
Page 117 of 141
(b)
any one from:
•
may be toxic (to cells / specific cells)
allow may harm / damage / kill cells / organs / tissues or may
cause cancer
•
to ensure safety or reduce risk or risk of litigation
allow may cause allergies / side effects
ignore harmful / dangerous unqualified eg harmful to body / people
•
nanoparticles may have different properties
•
to see if they pass into the body
1
(c)
any two sensible ideas from eg:
•
testing is expensive or testing costs money
allow it costs money
ignore litigation
•
testing is time consuming
•
don’t see any reason to test since normal sized particles (of titanium oxide) do not
cause harm
accept normal sun cream does not cause harm owtte
•
don’t want to risk not producing a popular product (owtte)
eg if unsafe will have to stop production or have to remove product
if toxic
•
testing process / unfavourable results might cause alarm / reduce sales / reduce
profit (less money)
•
do not want to be seen doing animal testing
2
[5]
M40.
(a)
2.8.3 on diagram as Xs / dots
or e
accept paired or unpaired
1
Page 118 of 141
(b)
any two from:
•
electrons in highest energy level or electrons in outer shell
•
electrons are delocalised or sea of electrons
•
electrons are free or electrons move around / flow
•
electrons carry charge / current
ignore carry electricity
2
[3]
M41.
(a)
(i)
Quality of Written Communication
The answer to this question requires ideas in good English in a sensible order with
correct use of scientific terms. Quality of written communication should be
considered in crediting points in the mark scheme.
maximum 2 marks if ideas not expressed well
layers / lattice / giant structure / regular pattern of atoms (diagram)
allow layers / lattice / giant structure / regular pattern of ions
do not accept particles
1
outer (shell) electrons
accept valence electrons
1
(free to) move (through whole structure)
accept delocalised / mobile / free
1
(ii)
the free electrons (allow the metal to conduct electricity)
accept electrons move / mobile / delocalised
1
(iii)
atoms / ions / layers can slide / slip / move over each other
1
(b)
(i)
copper oxide formed or Cu reacts with oxygen or Cu is oxidised
1
this is a poor conductor or gets in the way of free moving electrons or fewer mobile
electrons
do not accept electricity
1
Page 119 of 141
or
oxygen atoms / oxygen molecules / oxide ions in metal
do not accept oxygen pockets / bubbles
prevents / disrupts flow of electrons /
current or fewer mobile electrons (1)
do not accept macro explanations
do not accept electricity
(ii)
hydrogen reacts with oxygen or water is formed or hydrogen reduces
copper oxide etc.
1
[8]
M42.
(a)
Mr (SiO2) = 60
if Mr incorrect ecf for max 2
1
60 g SiO2 → 28 g Si
correct answer for 3 marks
1
2.14 g SiO2 → 1 g Si
allow 2, 2.1, 2.14 (or anything rounding to 2.14), 2.16 or 2.2
a unit is not required but an incorrect unit loses the third mark
OR Mr (SiO2) = 60 (1)
moles if silicon needed =
= 0.0357
mass of SiO2 needed = 0.0357 × 60 (1)
= 2.14 g (1)
allow 2, 2.1, 2.14 (or anything rounding to 2.14), 2.16 or 2.2
OR Mr (SiO2) = 60 (1)
mass SiO2 = 1 ×
(1)
= 2.14 g (1)
allow 2, 2.1, 2.4 (or anything rounding to 2.14), 2.16 or 2.2
3
(b)
(i)
MgO(s) + 2HCl(aq) → MgCl 2(aq) + H2O(l)
penalise incorrect symbols correctly balanced equation for 1 mark
state symbols for 1 mark
allow correct multiples / fractions
2
Page 120 of 141
(ii)
or
ignore inner shell electrons of silicon
allow correct drawings without symbols
must clearly indicate four shared pairs of electrons with one
electron from each atom
(iii)
Si
H
1
= 0.05
= 0.15
1
1
3
for whole number ratio can be implied
1
Si H3
accept H3 Si or any correct formula with 1:3 ratio
if in step 1 they get either of ratios incorrect they lose first 2 marks
but can be ecf for 3rd and 4th mark
evidence of mass / Ar
1 mark
proportions of each
whole number ratio
correct formula
1 mark
1 mark
1 mark
1
Page 121 of 141
(iv)
C
accept c
1
(c)
any four from:
•
giant structure / macromolecule / lattice / giant molecule
allow giant molecular / giant atomic structure
•
each silicon atom joined to four other atoms
(or diagram)
•
covalent bonds
•
bonds are strong or large amount of energy needed to break bonds
accept hard to break bonds
•
large number of bonds to be broken
mention of giant ionic structure or intermolecular forces or
intermolecular bonds max 1 mark
diamond or carbon discussion max 3 marks unless clearly linked
to silicon
4
[15]
M43.
answers apply to:
accept diagrams and/or descriptions
carbon dioxide CO2
ammonia NH3
methane CH4
water H2O
*outer electronic structure of one atom correct or needs
correct number of electrons to complete outer shell
1
*outer electronic structure of other atom correct or needs
correct number of electrons to complete outer shell
1
*one shared pair of electrons (as one covalent bond)
use of ions or reference to ionic bonding negates this mark
1
*outer electronic structure of compound correct or each atom now
has a full outer shell/noble gas electron structure
1
[4]
Page 122 of 141
M44.
(a)
calcium atom loses two electrons
accept diagrams with correct labelling
1
(each) fluorine atom gains one electron
accept two electrons transfer from a calcium atom to the two
fluorine atoms for these first two marks
1
forming full (outer) shells of electrons
accept forming full (outer) energy levels or noble gas electronic
structures
do not accept stable unless qualified
1
giving the ions Ca2+ and F−
1
attraction between ions of opposite charges
accept electrostatic attraction between ions
if candidate mentions sharing or pairing of electrons then no credit
if explanation is entirely correct but they state this is called
covalent bonding, the maximum mark is four
1
(b)
atoms of the same element
1
atomic number is same
accept each contains 92 or same number of protons
1
mass numbers differ or each has a different number of neutrons
1
one has 146 neutrons the other has 143 neutrons
accept one has three more or less neutrons than the other
1
(c)
(i)
349
1
(ii)
349g UF2 produces 235g U [1]
first mark can be awarded if answer is incorrect
answer = 117.5
1
[12]
M45.
(i)
can be from diagram chlorine (2.8).7.
accept chlorine needs one more electron
1
Page 123 of 141
can be from diagram shares a pair of electrons
1
shared pair of electrons is a covalent bond
do not accept ionic bond
1
(ii)
can be from diagram and appropriately annotated sodium (2.8). 1.
and chlorine (2.8).7
1
sodium loses one electron and chlorine gains one electron
1
Na+ and Cl– formed
1
bond formed between oppositely charged ions or ionic bond is formed
do not accept covalent bond
1
[7]
M47.
(a)
any (must be named)
1
(b)
F2
1
(c)
–/F–
1
(d)
(i)
covalent
1
(ii)
made of molecules etc.
type of bonding when non-metals react.
1
[5]
M48.
(a)
(i)
14 electrons =
gets 1 mark
2.8.4 =
gets 2 marks
2
(ii)
outer shell electrons
1
(iii)
same number of electrons in outer shell
1
Page 124 of 141
(b)
(1)
shiny
conducts electricity
(2)
oxide neutralises alkalis
covalent bonds
4
[8]
M49.
(i)
(ii)
electrons
for 1 mark
covalent
1
1
for 1 mark
(iii)
made of small molecules:
usually gas or liquid
) dependent on
have low melting points ) having first
have low boiling points ) point above
forces between molecules are weak
any 1 for 1 mark
3
[5]
M50.
(a)
8 marks
Particularly well structured answer with most points mentioned.
7-6 marks Well structured answer. The two metals will have been
compared rather than simply listing advantages/disadvantages. Most
of the advantages and disadvantages of each metal have been mentioned.
5-3 marks Some structure to the answer. An attempt to compare the metals
by giving some advantages and disadvantages.
2-1 marks Little structure or attempt to compare. Marks gained by listing a few
advantages or disadvantages.
Advantages of Nickel:
Relatively low cost which makes the sparking plugs cheaper to produce.
Quite high melting point which is needed because the temperature in the
engine is very high.
Good conductor of electricity needed to carry electricity into combustion
chamber to produce spark.
Disadvantages of Nickel:
Subject to corrosion in engine which means they only last a short time
because nickel is higher in reactivity than platinum.
Idea that this leads to reduced efficiency, unburnt petrol and air pollution.
Page 125 of 141
Advantages of Platinum:
Less susceptible to corrosion (not corroded) because platinum is very low in reactivity.
Idea that this improves efficiency and reduces pollution.Higher melting point than nickel to withstand the high temperatures in the
combustion chamber.
Last a lot longer than nickel electrodes due to low reactivity.
(Sensible extension here could be longer service intervals etc.)Good conductor of electricity as for nickel.
Extension here could be linked to the idea that the conductivity
does not deteriorate as quickly as nickel.)
Disadvantages of Platinum:
Cost which will make the sparking plug more expensive.
A good candidate might justify cost by longer life, better fuel consumption and
less pollution.
8
(b)
(i)
giant structure/lattice/regular arrangements of atoms
any for 1 mark
of atoms/of ions (provided free electrons mentioned)
either for 1 mark
delocalised or free electrons
for 1 mark
3
(ii)
electrons free/can move
for 1 mark each
2
[13]
M51.
(a)
2, 8, 8, 1
for 1 mark
1
Page 126 of 141
(b)
for 1 mark
Ignore symbol in middle but structure must be drawn NOT 2,7
If covalent; can score mark for changes but not for diagram
Arrow showing electron transfer from metal atom to non-metal atom = 2 marks
If the ions are not identified then cannot score mark for changes
4
[5]
M52.
(a)
4 HCl / 2H2O, allow multiples or fractions if whole equation balances
for 1 mark
1
(b)
germanium tetrachloride + water = germanium oxide + hydrochloric acid
If symbol equation given it must be correctly balanced
Allow germanium
for 1 mark
1
(c)
to purify the germanium oxide/remove impurities/give in
pure product/to make pure germanium
for 1 mark
1
ensure complete reaction/reaction does not give a good yield
not to increase efficiency/to purify germanium
for 1 mark
1
(d)
(i)
remove oxygen/addition of hydrogen/gain up electrons allow remove
oxygen molecules
(ii)
GeO2 = 73 + (2 × 16) = 105
mass of germanium = 525 × (73/105)
= 365 g
(or alternative methods)
apply consequential marking
for 1 mark each
3
Page 127 of 141
(e)
(i)
germanium is shiny/lustrous
conducts a small amount of electricity *
germanium oxide reacts with hydrochloric acid
(and) metal oxides react with acid
metal oxides are basic
metal oxides are reduced by hydrogen
Information must be taken from the passage.
Apply the list principle if more than three answers are given.
Assume the word ‘it’ refers to the metal.
any 3 for 1 mark each
3
(ii)
germanium is brittle
germanium tetrachloride is a (volatile) liquid
made of molecules
germanium tetrachloride has covalent bonding or when two non-metals
react they have covalent bonding
GaC14/the salt of germanium undergiven hydrolysis/reacts with water
germanium is not a good conductor of electricity*
* conductivity mark can only be given once
any 3 for 1 mark each
3
[13]
M53.
(a)
C16 H34
for 1 mark
1
(b)
electron
gains 1 mark
but shared electrons
gains 2 marks
2
[3]
##
(a)
potassium / K
for 1 mark
1
(b)
carbon dioxide / CO2
for 1 mark
1
(c)
losing
electrons
gaining
electrons
for 1 mark each
4
Page 128 of 141
(d)
(i)
power supply, (not mains)
beaker containing solution,
(inert) electrodes and circuit
ammeter or bulb/
(or see bubbling etc. at electrodes written by drawing)
for 1 mark each
4
(ii)
reading on ammeter/bulb lights / (solution) conducts (electricity)
bubbling / gas produced
hydrogen produced
chlorine / oxygen produced
ions move
to electrodes (must be linked to ions move)
negative ions move to the positive electrode
and/or positive ions move to the negative electrode
negative ions lose electrons
and/or positive ions gain electrons
any 3 for 1 mark each
3
[13]
##
(a)
covalent/description of covalent
for 1 mark
1
(b)
forces/bonds between the molecules/particles (not atoms) are weak
for 1 mark each
2
(c)
non-flammable so it will not burn etc.
extremely unreactive so it will not react with materials in the transformer,
does not conduct electricity so it can insulate the transformer
gas so it has freedom to move and insulate whole area
for 1 mark each
3
[6]
Page 129 of 141
M56.
(a) some electrons from outer shells
(some electrons) free to move/mobile
through whole structure/between atoms/sea of electrons
hold atoms together
for 1 mark each
or positive ions in a sea of electrons (owtte)
2 marks
atoms in regular structure/layers
giant structure
close packed
credit diagrams – look for labels
for 1 mark each any 4
4
(b)
(i)
electrons,
free to move (reference to electrons)
for 1 mark each
2
(ii)
layers/atoms can slide over each other
for 1 mark
1
(iii)
free electrons hold atoms strongly together/strong forces of attraction/bonds
(between atoms)/tight packing of atoms
for 1 mark
1
[8]
M57.
(a) made of layers
of carbon atoms
weak forces of attraction between layers (owtte) / weak
vertical bonds i.e.
candidate refers to the diagram
layers can slide over each other
layers peel off
each for 1 mark
(b)
because there are electrons
which are free (to move)
reason for free electrons / each carbon atom has 3 covalent bonds
each for 1 mark
to max 5
[5]
M58.
(a)
X – (metal) atom / ion
1
Y – electron
1
Page 130 of 141
(b)
free electrons or electrons move
1
(allow metal) atoms / ions to slide over each other
OR
bonding non - directional for 2 marks
1
[4]
M59.
(a) Quality of written communication: All scientific words used correctly
(covalent, bonds, atoms)
1
any two from
•
large numbers of covalent bonds
allow giant lattice / structure
•
between atoms
do not accept between molecules
•
(covalent) bonds strong
accept need much energy to break
2
Page 131 of 141
(b)
each carbon has 4 electrons
1
one shared pair
1
four shared pairs
1
[6]
M60.
(i)
1
Page 132 of 141
(ii)
weak forces
accept weak bonds
1
between molecules / intermolecular
reject intramolecular
1
[3]
M61.
(a)
Mg + 2H+ → Mg2+ + H2
* reactants correct in every detail
* products correct in every detail
if the spectator ions are sown then (1) mark should be credited but
only if they are shown correctly on both sides
e.g.
Mg + 2H+ + 2CI- → Mg2+ + 2CI- + H2
2
(b)
24 (parts) of magnesium → 2 (parts)
1
of hydrogen or equally clear working (so) 6 grams/g (are needed)
1
unit required
(c)
(i)
two (and no more) atoms shown to be sharing their single electrons
examples
do not credit if anything which contradicts the impression that these
are hydrogen atoms
1
(ii)
(single) covalent (bond)
1
(d)
(×100) = 6 (just 6 is worth (1) mark)
1
× 100 = 6 or similar is (0)
do not credit 5.8823529 and the like
1
[8]
Page 133 of 141
M62.
(a)
(i)
sodium........ positive or +
both required
1
chloride... negative or –
both required
do not credit chlorine
1
(ii)
ions not free (to move) in solid crystal / lattice
ions are free to move when sodium chloride is molten
1
or ions are mobile
do not credit when ions are molten
allow 'particles' for ions (1) mark
do not credit electrons etc
1
(iii)
dissolved in water
or in aqueous solution
accept in solution
accept in water
or when a gas/ vapour or solid it will not
1
(b)
(i)
40
1
(ii)
(total) number of protons and neutrons (in the nucleus)
1
(c)
(i)
2Ca + O2 -+ 2CaO
accept any 2n : n : 2n ratio
do not credit if any other change has been made
1
(ii)
any two from
electron(s) is / are lost
from the outer shell / orbit / ring
or from the shell furthest the nucleus
or from the 4th shell
two / both (electrons are lost)
accept two electrons are lost for (2)marks
accept both electrons are lost from the
atom for (1) mark
2
[10]
Page 134 of 141
##
(a)
covalent bonds
for 1 mark
1
(b)
any reference to shared electrons
gains 1 mark
but idea that bond is shared pair of electrons
gains 2 marks
2
[3]
##
(a)
Idea that
the electrons do not belong to specific atoms/delocalised electrons
[credit if done on appropriate diagram]
metal atoms form positive ions
the attraction which exists between particles with opposite charges, holds the metal together
no specific bonds exist between adjacent atoms/ions
atoms/ions can slide over each other so allowing metals to bend
each for 1 mark
5
(b)
some electrons in the structure are delocalised/free to move
for 1 mark
these free electrons carry the electric current
for 1 mark
from left to right across the period, atoms of elements have
more free electrons
gains 1 mark
but from left to right across the period, atoms of elements have more free
electrons because they have more electrons in the outer shells
gains 2 marks
4
[9]
M65.
(i)
carbon dioxide (allow CO2)
for 1 mark
1
(ii)
sodium nitrate (accept correct formula)
for 1 mark
1
[2]
Page 135 of 141
M66.
(a)
correct representation of 1 atom of hydrogen e.g.
gains 1 mark
but correct representation of 1 molecule of hydrogen e.g. or H-H
gains 2 marks
2
(b)
idea that:
hydrogen/metals form positive ions/lose electrons
gains 1 mark
but hydrogen and the metals form positive ions/lose electrons
gains 2 marks
hydrogen/non-metals form covalent bonds/share electrons
gains 1 mark
but hydrogen and the non-metals form covalent bonds/share electrons
gains 2 marks
4
[6]
M67.
(a)
(i)
2 H2 + O2 → 2 H2O (allow H2 + ½O2 → H2O)
both circled for 1 mark
1
(ii)
4 A1 + 3 O2 → 2 A12O3
all circled for 1 mark
1
(b)
idea that:
must end up with the same number of atoms
otherwise matter is shown to be lost/gained
doesn’t show correct amount of each element/compared
each for 1 mark
2
Page 136 of 141
(c)
idea that:
oxygen has 2 electrons short in outer shell ) in words or
chlorine has 1 electron short in outer shell ) indicated on diagram
(shared pair/covalent bond with) hydrogen
atom supplies one further electron*
*(but do not allow hydrogen gives away electron or ionic bond)
for 1 mark each
3
[7]
##
(a)
idea that
some of the outer electrons of the atoms are free to move
can move anywhere across the (giant) structure
the flow of electricity is a stream of electrons
each for 1 mark
or electrons carry a (negative electrical) charge
3
(b)
metal element
[shiny] appearance
[high] melting point
forms an oxide that reacts with acids to make a salt
1 of these for 1 mark
non metal element
forms an oxide that reacts with alkalis
with chlorine forms a molecular chloride
1 of these for 1 mark
semi-conductor suggests in between
this, or any other for 1further mark
[NB Maximum of 2 for arguing metal/non-metal only]
Under each head
1 wrong reason → maximum of 1 available
2 wrong reasons → no mark available]
3
[6]
M69.
(a)
2 Na + Cl2 → 2 NaCl allow 2 Na+ Cl– for 1 mark
(allow Na + ½Cl2 → Na Cl)
1
Page 137 of 141
(b)
(i)
idea that
•
it has strong (attractive) forces/bonds between ions / charged
particles
for 1 mark
(not ‘..it has a rigid structure’- this defines a solid or ‘...particles
close together’ – they are in a liquid)
1
(ii)
ideas that
•
there is increased vibration of ions / particles on heating
•
ions have sufficient energy to overcome attractive forces / to
break out of the
•
rigid structure / to move about
(must be in terms of increased energy of particles lions)
each for 1 mark
2
(iii)
•
ions can go to electrodes / ions are free to move
for 1 mark
[do not credit ‘ions carry charges’]
1
(c)
ideas that
•
it has stronger attractive forces between atoms/particles (not ‘ions’)
•
each carbon atom forms covalent bonds with neighbouring atoms
each for 1 mark
2
[7]
M70.
(a)
(i)
idea that
•
two hydrogen atoms share one pair of electrons
•
linked by a covalent bond
•
each then has two outer electrons / a full outer shell / two
•
electrons in the highest (occupied) energy level
(2 marks may be awarded for a correct electron diagram i.e. with electrons on
boundary of or within marked area).
any two for 1 mark each
2
Page 138 of 141
(ii)
idea that
•
helium atoms do not give / take / share electrons / react
•
because the (outer) shell / orbit is full
or
•
highest (occupied) energy level is full
(but not just “contains two electrons”)
for 1 mark each
2
(b)
idea that
•
the (attractive) forces between molecules are weak
(not bonds between atoms)
•
so little energy is required / it is easy for molecules to escape from the liquid*
/ escape from other molecules*
(allow evaporate / change into a gas)
for 1 mark each
2
[6]
M71.
(a)
idea that
•
copper has free electrons / electrons that move
throughout the structure
gains 1 mark
but
•
in copper, electrons from the highest (occupied) energy
level /outer shell, are
free / can move throughout the structure
gains 2 marks
2
Page 139 of 141
(b)
idea that
•
in graphite, only three bonds are formed by each carbon atom
for 1 mark
•
one outer electron (per atom), free to move
for 1 mark
•
an electric current is a flow of (free) electrons*
for 1 mark
(* this mark to be given in either (a) or (b) but not in both)
3
[5]
Page 140 of 141
Page 141 of 141