S.4 Chemistry Supplementary Exercise 2013-2014
Name: _________________________________ Block: _____
Mark:
Class and class number: S.4 ___ (
)
1.
/ 110
Which of the following diagrams can represent a mixture of two elements?
(In these diagrams,
and
represent a nitrogen atom and an oxygen atom respectively.)
A.
B.
C.
D.
2.
Which of the following correctly describes the sequence of procedures to separate chalk, salt and water
from a mixture of chalk powder and salt solution?
A. Evaporation, crystallization
B. Crystallization, filtration, distillation
C. Filtration, distillation
D. Filtration, evaporation
3.
How many electrons and neutrons are there in a doubly charged cation formed from
Number of electrons
Number of neutrons
A.
26
30
B.
26
32
C.
28
28
D.
4.
5.
28
3 moles of iron (III) sulphate contains
A. 3 moles of molecules.
C. 6 moles of anions.
A part of the periodic table is shown below.
F.4/Summer Assignment/2013-2014/P.1
30
B.
D.
6 moles of cations.
9 moles of atoms.
58
28
Ni?
Which of the following statements is/are correct?
(1) ‘a’ has an octet structure.
(2) ‘b’ and ‘e’ are alkali metals.
(3) ‘c’ and ‘d’ are semi-metals.
A. (1) only
6.
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
Astatine (At) is a Group VII element. Which of the following statements concerning astatine are
correct?
(1) It is a halogen.
(2) The compound formed between carbon and astatine has a simple molecular structure.
(3) The chemical formula of the compound formed between magnesium and astatine is MgAt.
A. (1) and (2) only
7.
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
A color patch moves towards the left in the following set-up.
The colored crystals on the filter paper should be
A. chromium (III) sulphate.
C. potassium permanganate.
8.
B. iron (III) chloride.
D. sodium sulphate.
A compound contains 54.5% by mass of carbon, 9.10% by mass of hydrogen and the rest being oxygen.
The relative molecular mass of this compound is 88.0. What is its molecular formula?
(Relative atomic masses: H = 1.0; C = 12.0; O = 16.0)
A. C2H4O
B. C3H4O3
C. C4H8O2
9.
Which of the following electron diagrams is correct?
A.
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B.
D. C5H12O
C.
D.
10. Consider the following two elements.
Element
Atomic number
Relative atomic mass
P
7
14.0
Q
20
40.1
Elements P and Q combine to form a compound. Which of the following statements concerning the
compound are correct?
(1) It has a high melting point.
(2) It is a crystalline solid at room temperature and pressure.
(3) Its formula mass is 68.1.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
11. Consider the following experiment:
During the experiment, a gas is liberated. The gas can burn at the end of the delivery tube. X could be
A. copper
B. lead
C. silver
D. zinc
12. What is the percentage by mass of oxygen in Al(NO3)3˙H2O?
(Relative atomic masses: H = 1.0; N = 14.0; O = 16.0; Al = 27)
A. 29.9%
B. 33.6%
C. 44.9%
D. 69.3%
13. The following table shows some properties of four solids, W, X, Y and Z.
Properties
W
X
Y
Z
Melting point (°C)
2 300
800
80
1 200
Soluble in water?
no
yes
no
no
Conducts electricity in solid state?
no
no
no
yes
Conducts electricity in molten state?
no
yes
no
yes
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What is the correct classification of the solids?
Metallic
Covalent network
A.
W
X
B.
X
Y
C.
Y
Z
D.
Z
Ionic
Y
Z
W
Simple molecular
Z
W
X
X
Y
W
14. The diagram below shows the structure of an allotrope of carbon.
Which of the following statements concerning the allotrope are correct?
(1) It has a slippery feel.
(2) It has a low melting point.
(3) It is used as electrodes in dry cells.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
15. Different metals are dropped into water or dilute hydrochloric acid. Assuming that the experimental
conditions are the same, which of the following comparisons concerning the initial rates of hydrogen
formation is correct?
A.
B.
C.
Initial rate of
hydrogen formation
Ca and H2O
Cs and H2O
Na and H2O
>
>
>
Initial rate of
hydrogen formation
Ba and HCl
Ca and H2O
Cs and H2O
D.
Zn and HCl
>
Na and H2O
16. Consider the following chemical equation:
Na2S2O3(aq) + 2HCl(aq)  2NaCl(x) + SO2(g) + H2O(y) + S(z)
Which of the following combinations is correct?
x
y
z
A.
aq
l
s
B.
aq
l
aq
C.
l
aq
s
D.
l
aq
aq
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17. Consider the following equation:
V2O5 + xH+ + yCl–  yVO2+ + Cl2 + zH2O
(V is the symbol for the element vanadium.)
Which of the following combinations is correct?
A.
B.
C.
D.
x
3
3
6
6
y
1
3
2
3
z
3
1
3
2
18. Iron (II) nitrate solution should NOT be stored in
(1) a zinc container
(2) a plastic container
(3) a lead container
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
19. Decomposition of solid KClO3 gives KCl and O2 as the only products. What is the mass of O2 produced
when 49.0 g of KClO3 undergoes complete decomposition?
(Relative atomic masses: O = 16.0; Cl = 35.5; K = 39.1)
A. 14.4 g
B. 19.2 g
C. 24.0 g
D. 28.4 g
20. A sample of concentrated nitric acid has a density of 1.34 g cm-3 and contains 71.0% of nitric acid by
mass. What is the molarity of the nitric acid sample?
(Relative atomic masses: H = 1.0; N = 14.0; O = 16)
A. 9.38 mol dm-3
B. 9.51 mol dm-3
C. 13.5 mol dm-3
D. 15.1 mol dm-3
21. 25.0 cm3 of a 0.200 M acid solution requires 30.0 cm3 of 0.500 M potassium hydroxide solution for
complete reaction. What is the basicity of the acid?
A. 1
B. 2
C. 3
D. 4
Directions: Questions 22 and 23 refer to the following experiment.
Four iron nails were wrapped with different metal strips. Rust indicator solution containing potassium
hexacyanoferrate (III) and phenolphthalein was poured into the following glass dishes to cover the iron nails.
The dishes were allowed to stand in air for some time.
iron strip
magnesium strip
silver strip
zinc strip
dish 1
dish 2
dish 3
dish 4
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22. In which of the dish(es) would the iron nail rust?
A. Dish 1 only
B. Dishes 1 and 3 only
C. Dishes 2 and 4 only
D. Dishes 2, 3 and 4 only
23. Which of the following combinations is correct?
Dish
Color change of rust indicator
A.
B.
C.
D.
1
2
3
4
no color change
a blue color appeared
a brown color appeared
a pink color appeared
24. Which of the following methods should be used to distinguish copper from a mixture of copper and
copper (II) oxide?
A. Adding dilute hydrochloric acid to the two substances.
B. Adding dilute sodium hydroxide solution to the two substances.
C. Adding distilled water to the two substances.
D.
Heating two substances strongly.
25. Consider the aqueous solutions below:
(1) 2M citric acid
(2) 2M hydrochloric acid
(3) 2M ammonia solution
Which of the following lists the solutions in increasing order of pH?
A. (1), (2), (3)
B. (2), (1), (3)
C. (3), (1), (2)
D. (3), (2), (1)
26. Which of the following pairs of solutions would form a precipitate when they are mixed?
(1) K2SO4(aq) + NaCl(aq)
(2) NaOH(aq) + NiSO4(aq)
(3) (NH4)2CO3(aq) + CaCl2(aq)
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
27. The following table shows some information on mixing acids and alkalis:
Mixture
3
Temperature rise (°C)
–3
25 cm of 1 mol dm HCl(aq) +
25 cm3 of 1 mol dm–3 NaOH(aq)
x
50 cm3 of 1 mol dm–3 HCl(aq) +
50 cm3 of 1 mol dm–3 NaOH(aq)
y
50 cm3 of 1 mol dm–3 HNO3(aq) +
50 cm3 of 1 mol dm–3 KOH(aq)
z
Which of the following concerning the values of temperature rise is correct?
A. x < y = z
B. x < y < z
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C. x = y = z
D. x > y > z
28. The following set-up was used to investigate the tendency of four metals W, X, Y and Z to form ions.
The voltmeter reading for each metal strip was recorded in the following table:
Metal strip under
test
Direction of electron flow
in the external circuit
Voltage recorded (V)
W
W to Sn
+0.46
X
Sn to X
–0.38
Y
Y to Sn
+0.80
Z
Sn to Z
–0.72
Which of the following represents the ascending order of tendency of metals W, X, Y and Z to form
ions?
A. Z < W < Y < X
B. Z < X < W < Y
C. Y < W < X < Z
D. Y < X < W < Z
Directions: Questions 29 and 30 refer to the following rechargeable nickel-cadmium cell.
The following equation represents the reaction that occurs when the cell is supplying electricity.
NiO2(s) + Cd(s) + 2H2O(l)  Cd(OH)2(s) + Ni(OH)2(s)
29. Which of the following ionic half-equations represents the chemical change that occurs at the anode
when the cell is supplying electricity?
A. Cd(s) + 2OH-(aq)  Cd(OH)2(s) + 2eB.
C.
D.
NiO2(s) + 2H2O(l) + 2e-  Ni(OH)2(s) + 2OH-(aq)
NiO2(s) + 2H2O(l)  Ni(OH)2(s) + 2OH-(aq) + 2eCd(s) + 2OH-(aq) + 2e-  Cd(OH)2(s)
30. In this cell, the oxidizing agent is
A. NiO2(s)
B. Cd(s)
F.4/Summer Assignment/2013-2014/P.7
C. Cd(OH)2(s)
D. H2O(l)
Directions: Each question below (Questions 31-33) consists of two separate statements. Decide whether
each of the two statements is true or false; if both are true, then decide whether or not the second statement
is a correct explanation of the first statement. Then select one option from A to D according to the following
table:
A
B
C
D
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
Only one statement is true while the other is false.
Both statements are false.
1st statement
2nd statement
31. Helium exists as diatomic molecules.
There are two electrons in the outermost shell of
a helium atom.
32. Lemon juice can be used as the electrolyte
for a simple chemical cell.
Lemon juice is acidic.
33. When dilute sodium sulphate solution
is electrolyzed using graphite electrodes,
sodium metal is formed.
Sodium ion is a stronger oxidizing agent than
hydrogen ion.
Section B: Question-Answer Book
Answer ALL questions.
1.
(a) The following table shows the information about the four isotopes of sulphur.
Isotope
(i)
Relative abundance (%)
32
S
95.02
33
S
0.75
34
S
4.21
36
S
0.02
What is the meaning of the term ‘isotope’?
(ii) Calculate the relative atomic mass of sulphur.
F.4/Summer Assignment/2013-2014/P.8
(2 marks)
(2 marks)
(b) Propellants are used to make rockets fly up into the atmosphere. The Chinese were the first to use
gunpowder as a propellant. Gunpowder contains sulphur, potassium nitrate and carbon. When the
gunpowder is ignited, the following reaction occurs:
2 KNO3(s)
(i)
+ S(s)
+ 3 C(s)
K2S(s)
+
N2(g)
+ 3CO2(g)
+
heat
Based on the above information, explain why the gunpowder can be used as propellants.
(1 mark)
(ii) Draw the electron diagrams of K2S and N2, showing electrons in the outermost shells only.
(2 marks)
2.
The following diagram shows a flowchart starting from quicklime (calcium oxide).
quicklime
Process 1
limewater
Process 2
calcium carbonate
(a) Suggest how quicklime can be converted to limewater in Process 1.
(0.5 mark)
(b) Suggest how calcium carbonate can be obtained from limewater in Process 2.
(0.5 mark)
(c) Both quicklime and calcium carbonate are white solids.
(i)
Suggest how you can show that both quicklime and calcium carbonate are calcium
compounds.
(1 mark)
(ii) Suggest a chemical method to distinguish between quicklime and calcium carbonate.
(2 marks)
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(d) Suggest ONE use of quicklime.
3.
(1 mark)
XO is an oxide of metal X. Upon heating, XO decomposes to give X and oxygen only.
(a) Write a chemical equation for the decomposition of XO.
(1 mark)
(b) In an experiment, 4.20 g of XO completely decomposes to give 3.89 g of X. Calculate the relative
atomic mass of X. (Relative atomic mass: O = 16.0)
(2 marks)
(c) Name metal X.
(1 mark)
4.
The diagrams below show part of two substances at very low temperature.
A
(whole
molecule)
C
D
B
Diagram 1: dry ice
(a) (i)
Diagram 2: quartz
Identify the particles A, B, C and D.
(ii) Particle B and particle C are in some way common to each other. What is it?
(b) What type(s) of force(s) is/are present in each of the two substances?
F.4/Summer Assignment/2013-2014/P.10
(2 marks)
(1 mark)
(2 marks)
(c) Explain why the two substances have different boiling points.
5.
(2 marks)
(a) Suggest a suitable metal for making each of the following items and state one property of the
metal related to your choice.
(2 marks)
Item
Metal
Property
(i) Railway tracks
(ii) Cooking pans
5.
(b) A student proposed some metals for making the following items. The chosen metals were all
considered inappropriate. Explain why the metals are inappropriate.
(2 marks)
Item
Metal
(i) Coating on food can
Chromium
(ii) Metal block on ship body
6.
Reason for inappropriate choice
Tin
Some hazard warning labels are shown below:
oxidizing
explosive
flammable
corrosive
(a) Which label(s) should be shown on a bottle of concentrated nitric acid?
(1 mark)
(b) A reaction occurs when concentrated nitric acid is added to a piece of copper.
(i)
State ONE observation of the reaction.
F.4/Summer Assignment/2013-2014/P.11
(1 mark)
(ii) Write two ionic half-equations for the reaction.
(2 marks)
(iii) Explain what property of the acid is involved in the reaction in terms of oxidation number.
(2 marks)
(c) Suppose you need to dilute 50.0 cm3 of 5M nitric acid into a 1M nitric acid, describe how you
could carry out the dilution.
(3 marks)
7.
The following experimental set-up was used to determine the empirical formula of an oxide of copper.
burning off excess
town gas
town gas
porcelain boat containing
heat
oxide of copper
In the experiment, 9.54 g of an oxide of copper, after complete reaction, produced 7.62 g of copper.
(a) Deduce the empirical formula of the oxide of copper.
(2 marks)
(Relative atomic masses: O = 16; Cu = 63.5)
(b) It is known that the major component of the town gas is hydrogen. Write an equation for the
reaction that occurred in the combustion tube.
(1 mark)
(c) State ONE potential hazard associated with this experiment and suggest a safety precaution for the
hazard.
F.4/Summer Assignment/2013-2014/P.12
(2 marks)
(d) Explain why it was necessary to pass town gas through the tube for some time after the heat was
removed.
(1 mark)
(e) A student claims that it is possible to deduce the empirical formula of aluminium oxide using a
similar method. Comment on the student’s claim.
8.
(1 mark)
25 cm3 of calcium hydroxide solution was titrated against 2M hydrochloric acid. The electrical
conductivity of the solution was measured after each addition of hydrochloric acid. The result is plotted
in the graph below.
electrical conductivity
(current/mA)
A
C
B
volume of 2M HCl added (cm3)
(a) (i)
Name the reaction between calcium hydroxide solution and hydrochloric acid. (1 mark)
(ii) Write an equation for the reaction involved in (i).
(1 mark)
(b) Based on the equation in (a)(ii), explain why there is a drop of electrical conductivity from A to
B.
(1 mark)
(c) What is the volume of hydrochloric acid required to neutralize completely 25 cm3 of calcium
hydroxide solution?
(1 mark)
(d) Calculate the molarity of the calcium hydroxide solution.
F.4/Summer Assignment/2013-2014/P.13
(2 marks)
9.
A chemical cell is set up using the following materials and apparatus:
1 M iron (II) sulphate solution, 1 M acidified potassium dichromate solution, beakers,
filter paper with potassium nitrate solution, carbon rods, connecting wires and voltmeter
(a) Draw a labelled diagram to show the set-up of the chemical cell.
(2 marks)
(b) State the observable changes in the two half-cells.
(2 marks)
(c) Write an ionic equation for the overall reaction that occurs in the chemical cell.
(1 mark)
10. Power showers often produce brown-colored water when first switched on after being unused for a few
days. The discoloration in the water is due to the formation of iron (III) hydroxide caused by rusting of
the steel shower parts.
(a) The formation of ‘rust’ takes place in three stages in the presence of air and water.
Stage 1 Iron metal forms aqueous Fe2+ ions.
Stage 2 Fe2+ ions are oxidized.
Stage 3 Iron (III) hydroxide is precipitated out of solution.
(i)
Write the ionic half-equation for the formation of Fe2+ ions from Fe in Stage 1. (1 mark)
(ii) Write the ionic half-equation for the formation of OH- ions from O2 and H2O.
F.4/Summer Assignment/2013-2014/P.14
(1 mark)
(iii) Write an ionic equation for the precipitation reaction in Stage 3.
(1 mark)
10. (b) The amount of Fe2+(aq) in a sample of water can be found by titration with a standard solution of
acidified potassium permanganate.
(i) State the definition of a ‘standard solution’.
(1 mark)
(ii) 25.0 cm3 of an acidified solution containing Fe2+(aq) reacts completely with 10.0 cm3 of
0.0070M acidified potassium permanganate solution. The equation for the reaction is given
below.
5Fe2+(aq)
+ 8H+(aq)
+ MnO4-(aq)
5Fe3+(aq)
+ Mn2+(aq)
Calculate the molarity of Fe2+(aq) in the sample.
(iii) Explain why it is NOT necessary to add an indicator for this titration.
+ 4H2O(l)
(2 marks)
(1 mark)
11. A 2M copper (II) chloride solution is electrolyzed using carbon electrodes.
(a) Describe and explain what would happen at the two carbon electrodes.
F.4/Summer Assignment/2013-2014/P.15
(4 marks)
11. (b) Write ionic half-equations for the chemical changes that occur at electrodes X and Y respectively.
(2 marks)
(c) What would be observed in the electrolyte after some time? Explain your answer.
(1 mark)
For question 12, you are required to give answers in paragraph form. For this question, 6 marks will
be awarded for chemical knowledge and 3 marks for effective communication.
12. Describe how you would prepare crystals of potassium nitrate, from potassium hydroxide solution and
dilute nitric acid, in the school laboratory.
(9 marks)
-End of Paper-
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