Q1.
Read the information in the box and then answer the questions.
Sun Creams
Sun creams contain titanium oxide. This compound absorbs harmful radiation.
Traditional sun creams contain normal-sized particles of titanium oxide.
Normal-sized particles of titanium oxide are known to be safe to put on the skin.
Many new sun creams contain nano-sized particles of titanium oxide.
Experiments suggest that nano-sized particles might pass through the pores of the skin more easily
than normal-sized particles.
(a)
Explain why nano-sized particles might pass more easily through the pores of the
skin than normal sized particles.
........................................................................................................................
........................................................................................................................
(1)
(b)
Using these sun creams is beneficial because they absorb harmful radiation.
Suggest one possible risk of using these sun creams.
........................................................................................................................
........................................................................................................................
(1)
(Total 2 marks)
Q2.
This drill contains an electric motor.
Page 1
The diagram below shows the main parts of an electric motor.
The carbon contacts are made of graphite. Springs push the contacts against the copper
ring.
The carbon 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.
(a)
Using this information give two properties that make graphite suitable for making
the carbon contacts.
1 .......................................................................................................... .........................
............................................................................................................................. ........
2 .............................................................................................. .....................................
............................................................................................................................. ........
(2)
(b)
(i)
Draw a ring around the correct word in each box to complete the sentence.
Each carbon atom in graphite is joined to
two
three
covalent
other carbon atoms by
ionic
Page 2
bonds.
four
metallic
(2)
(ii)
Tick ( ) the statement which explains why graphite is soft and slippery.
Statement
Tick ( )
It is made of layers of atoms.
It is made of small molecules.
It is an ionic compound.
(1)
(Total 5 marks)
Q3.
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.
Page 3
Use words from the box to complete the sentences.
covalent
giant
four
high
low
six
small
weak
One reason for using silica to make bricks for high-temperature furnaces is that silica has
a
.......................................... melting point.
Silica has this property because it is a .......................................... structure in which each
silicon
atom is joined to .......................................... oxygen atoms by ..........................................
bonds.
(Total 4 marks)
Q4.
This label was on a container of graphite lubricant.
Super G
Graphite Lubricant
Super G forms a thin anti-friction film on metal surfaces. It provides good lubrication when metal
parts rub against each other.
(a)
Give one reason why a lubricant is used when metal parts rub against each other.
.....................................................................................................................................
............................................................................................................................. ........
(1)
(b)
The diagram shows the arrangement of atoms in graphite.
Page 4
(i)
Draw a ring around the type of atoms in graphite.
aluminium
carbon
silicon
(1)
(ii)
Graphite is a good lubricant because it is slippery. Use the diagram to explain
why graphite is slippery.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 4 marks)
Q5.
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.
Page 5
‘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.
(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)
Q6.
Magnesium oxide is a compound, made up of magnesium ions and oxide ions.
Page 6
(a)
What is the charge on each magnesium ion? .............................................................
(1)
(b)
Explain how the magnesium ions get this charge.
............................................................................................................................. ........
.....................................................................................................................................
............................................................................................................................. ........
(2)
(Total 3 marks)
Q7.
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.
Page 7
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)
(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.
.....................................................................................................................................
Page 8
............................................................................................................................. ........
.....................................................................................................................................
............................................................................................................................. ........
(2)
(Total 4 marks)
Page 9
M1.
(a)
because nano-sized particles are smaller than normal sized particles
1
(b)
may cause harm when they are inside the body
1
[2]
M2.
(a)
any two from:
•
conducts electricity
•
soft
•
slippery
•
high melting point
ignore hardwearing / does not stick
apply list principle
2
(b)
(i)
three
1
covalent
1
(ii)
it is made of layers of atoms
1
[5]
M3.
high
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1
giant
allow covalent
1
four
1
covalent
1
[4]
M4.
(a)
reduce wear of metal ie don’t get damaged
or other sensible answer
or
stop / reduce friction
accept stop metal heating up
accept move more smoothly
ignore make it slippery / rub more smoothly
or
prevent seizing
accept can move freely
1
(b)
(i)
carbon
1
(ii)
layers (of atoms)
1
can slide / slip over each other
allow slip off
or
weak forces of attraction / weak bonds (between layers)
allow no bonds
accept there are weak forces of attraction for
1 mark even when there is no reference to layers
accept atoms slide over each other (for 1 mark)
an answer which only states there are weak bonds would
gain 0 mark when there is no reference to layers
Page 11
weak covalent bonds = 0 marks
1
[4]
M5.
(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]
##
(a)
positive
for 1 mark
1
Page 12
(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]
M7.
(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
(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)
Page 13
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]
Page 14