Download Year 8 Revision Questions Chemistry

Year 8
Revision
Questions
Chemistry
Barnard Castle School
1
1.
The drawings show six objects made from different materials.
not to scale
(a) Fill the gaps in the sentences below.
The objects are made from materials that are all types of ...........................
1 mark
All the materials are good conductors of electricity and ...............................
1 mark
(b)
From the drawings above give one object that could rust.
......................................................................................................................
1 mark
(c)
The drawing below shows part of an electric cable and a plug.
(i)
What material could be put around the wires to insulate them?
.............................................................................................................
1 mark
(ii)
Why is this insulating material needed?
.............................................................................................................
1 mark
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(d)
Which pair of objects is attracted to a magnet?
Tick the correct box.
1 mark
maximum 6 marks
2.
The list below shows properties that different elements can have.
 magnetic
 can be compressed
 very high melting point
 very low melting point
 good conductor of heat
 poor conductor of heat
 good conductor of electricity
 poor conductor of electricity
(a)
Which two properties from the list above make aluminium suitable for saucepans?
1. .................................................................................................................
2. .................................................................................................................
2 marks
(b) Which property in the list above explains why:
(i)
copper is used in the cable of a television?
.............................................................................................................
1 mark
(ii)
a lot of oxygen gas can be pumped into a very small container?
.............................................................................................................
1 mark
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Maximum 4 marks
3
3.
(a)
The drawings below show three objects made from copper.
Draw a line from each object to the reason for using copper for that object.
Draw only three lines.
object made
from copper
reason for using
copper
It does not rust.
base of a saucepan
It is a good conductor
of electricity.
coin
It is a good conductor
of heat.
wires in a cable
It is not magnetic.
3 marks
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4
(b)
Brass is a mixture of copper and zinc. Some keys are made from brass
Why is brass more suitable than copper for a key?
Tick the two correct boxes.
Brass does not bend as
easily as copper.
Brass is a paler colour than
copper.
Brass is harder than
copper.
Brass is not as shiny as
copper.
Brass is not such a good
conductor of electricity
as copper.
Brass is not such a good
conductor of heat as
copper.
2 marks
(c) Zinc melts at 420ºC.
Copper melts at 1085ºC.
A scientist heated a mixture of pieces of zinc and pieces of copper to 600ºC in a dish.
What would be in the dish at 600ºC?
liquid zinc and liquid copper
liquid zinc and solid copper
solid zinc and liquid copper
solid zinc and solid copper
1 mark
maximum 6 marks
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5
4.
Part of the reactivity series of metals is shown below.
most reactive
potassium
sodium
magnesium
aluminium
iron
lead
least reactive
(a)
copper
Dan added a piece of magnesium to a solution of copper sulphate.
A displacement reaction took place.
The word equation for the reaction is shown below.
magnesium + copper sulphate  magnesium sulphate + copper
Why is this called a displacement reaction?
......................................................................................................................
......................................................................................................................
1 mark
(b)
Look at each pair of chemicals in the table below.
Use the reactivity series to predict whether a displacement reaction would take place.
Write yes or no in the second column and give the reason for your decision.
pairs of chemicals
Does a displacement
reaction take place?
yes or no
reason
iron + sodium chloride
magnesium + lead nitrate
2 marks
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(c)
Dan wanted to find out where zinc should be placed in the reactivity series.
(i)
What tests should Dan do to find the correct position of zinc in the reactivity series?
.............................................................................................................
.............................................................................................................
.............................................................................................................
1 mark
(ii)
How would Dan use his test results to decide where to put zinc in the reactivity
series?
.............................................................................................................
.............................................................................................................
.............................................................................................................
1 mark
maximum 5 marks
5.
(a)
George used the apparatus below to find out what substances are produced when
methanol burns.
As the methanol burned, two different gases were produced.
(i)
One of these gases condensed in the U-tube to give a colourless liquid. Give the
name of this liquid.
........................................................
1 mark
(ii)
The other gas turned the lime water cloudy.
Give the name of this gas.
........................................................
1 mark
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(b) Methanol is sometimes used in antifreeze. It can be added to water in car windscreen
wash-bottles to prevent the water from freezing in cold conditions.
(i)
The label on the bottle of antifreeze has two hazard warning symbols. What two
precautions would you need to take when using this antifreeze?
1. .........................................................................................................
.............................................................................................................
2. .........................................................................................................
.............................................................................................................
1 mark
(ii)
Water freezes at 0°C. The label on the bottle shows how the freezing point changes
when different amounts of antifreeze are added to water.
Terry put a mixture containing 10% antifreeze into the wash-bottle of his car. During
the night the temperature dropped to –14°C.
The wash-bottle burst.
Explain why the wash-bottle burst.
.............................................................................................................
.............................................................................................................
.............................................................................................................
.............................................................................................................
2 marks
Maximum 5 marks
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8
6.
(a)
Sasha placed small samples of four different metals on a spotting tile.
She added drops of calcium nitrate solution to each metal.
spotting tile
copper
iron
magnesium
zinc
Sasha repeated the experiment with:
 fresh samples of the four metals and copper nitrate solution
 fresh samples of the four metals and iron nitrate solution.
Will a reaction take place when each of the metals is added to each of
the solutions?
Use the reactivity series below to help you.
most reactive
least reactive
calcium
magnesium
aluminium
zinc
iron
lead
copper
In the table below:
 place a tick,
, to show that a reaction took place
 place a cross, X, to show that no reaction took place.
Two have been done for you.
metal
salt solution
copper
iron
magnesium
zinc
calcium nitrate
copper nitrate
iron nitrate
X
X
3 marks
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9
(b)
Three pairs of chemicals are listed below.
A reaction only takes place with two of the pairs.
Draw a line from each reaction to the correct result.
Draw only three lines.
pair of chemicals
result
calcium carbonate + hydrochloric acid
no reaction
magnesium + hydrochloric acid
a chloride, carbon dioxide
and water are formed
copper + hydrochloric acid
a chloride and hydrogen
are formed
2 marks
maximum 5 marks
7.
The table shows the melting points and boiling points of four substances present in the air.
(a)
substance
melting point, in °C
boiling point, in °C
carbon dioxide
–78
–78
nitrogen
–210
–196
oxygen
–219
–183
water vapour
0
100
What happens to a piece of solid carbon dioxide if it is heated from –100°C to –78°C?
.....................................................................................................................
.....................................................................................................................
1 mark
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10
(b) ‘Liquid air’ can be formed from air in a heat exchanger. As the air passes through, thermal
energy is transferred from the air to the surroundings. This is shown in the flow diagram
below.
thermal energy
thermal energy
separator
heat exchanger
water
(i)
carbon
dioxide
'liquid air'
(a mixture of liquid oxygen
and liquid nitrogen)
Suggest a likely temperature for the ‘liquid air’ that leaves the heat exchanger.
................°C
1 mark
(ii)
Use the information in the table to explain why carbon dioxide and water vapour
need to be removed from the air before it is pumped through pipes to the heat
exchanger.
State the consequences of not removing these two gases.
.............................................................................................................
.............................................................................................................
.............................................................................................................
2 marks
(c) The ‘liquid air’ is a mixture of liquid nitrogen and liquid oxygen.
Use the information in the table to suggest how liquid oxygen could be obtained from the
mixture.
.....................................................................................................................
1 mark
(d) A room measures 4 m x 3 m x 2.5 m.
(i)
The density of air is approximately 1.2 kg/m3.
What is the approximate mass of air in the room?
Give the unit.
.............................................................................................................
.............................................................................................................
2 marks
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11
(ii)
If the air in the room is cooled to a low enough temperature, it will change from a
gas to a liquid.
The density of ‘liquid air’ is 1125 kg/m3. What volume of ‘liquid air’ would the air in
the room produce? Give the unit.
.............................................................................................................
1 mark
(iii)
How does the distance between the particles in atmospheric air compare to the size
of the particles themselves?
.............................................................................................................
1 mark
Maximum 9 marks
8.
A teacher set up the following apparatus to separate the chemicals in cigarette smoke.
The chemicals pass through the apparatus in the direction of the arrows.
burning
cigarette
cotton
wool
ice
cubes
A
(a)
lime water
water collects
here
B
C
In A, a brown sticky substance collected on the cotton wool. This substance causes lung
cancer. Give the name of the brown substance.
..............................................
1 mark
(b)
As the cigarette burned, water vapour was produced and water collected in B.
(i)
Why were ice cubes needed in B?
.............................................................................................................
.............................................................................................................
1 mark
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(ii)
In the boxes below, draw the arrangement of particles of water vapour and particles
of liquid water.
Use a circle, O, to represent each particle.
particles of
water vapour
particles of
liquid water
2 marks
(c)
The lime water in C became cloudy. What gas turns lime water cloudy?
................................................
1 mark
Maximum 5 marks
9.
A section of the periodic table of elements is shown below.
H
He
(a)
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
Where in this section of the periodic table are the metals found?
......................................................................................................................
1 mark
(b)
Sodium chloride is formed when sodium and chlorine combine together in a
chemical reaction.
Write the symbols for sodium and chlorine.
sodium
…………………………………..
chlorine
…………………………………..
2 marks
(c) The formula for a substance is MgS. What is the name of this substance?
......................................................................................................................
1 mark
Barnard Castle School
13
(d)
Give the name of one element in the table above which is a gas at room
temperature and in which the atoms are joined together in molecules.
......................................................................................................................
1 mark
Maximum 5 marks
10.
(a)
Complete the word equation below for the reaction between calcium carbonate and
hydrochloric acid.
calcium
carbonate

hydrochloric
acid
 .......... .......... .......... ..... 
carbon
dioxide
 water
1 mark
Limestone is mainly calcium carbonate. It is weathered by acids in the air or in soil.
(b)
In June 1990, a Year 9 class planned a long-term investigation into the chemical
weathering of limestone by acids in soil.
They put limestone chippings of similar size in three nylon mesh bags.
They buried the bags outside in soils of different pH.
(i)
Chemical weathering took place in sample A, and the mass of the sample
decreased.
Give the reason for the decrease in mass. Use the word equation above to help
you.
.............................................................................................................
.............................................................................................................
1 mark
(ii)
The pupils predicted that chemical weathering would not take place in samples B
and C.
Give the reason for their prediction.
.............................................................................................................
.............................................................................................................
1 mark
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14
(iii)
Some chemical weathering did take place in samples B and C.
What could have changed the conditions in these soils to cause weathering to take
place?
.............................................................................................................
1 mark
(c) The table shows how the mass of each sample changed between the years 1990 and
2000.
mass, in g
year
sample A, at
pH 5
sample B, at
pH 7
sample C, at
pH 8
1990
1000
1000
1000
1995
980
992
997
2000
960
984
995
In 2000, a year 9 class buried another identical 1000 g sample of limestone chippings in
soil of pH 6.
(i)
Use the results in the table to predict an approximate value for the mass of this
sample in 2010.
................. g
1 mark
(ii)
Why is it not possible to be certain what the mass of this sample will be in 2010?
.............................................................................................................
.............................................................................................................
1 mark
Maximum 6 marks
Barnard Castle School
15
11.
Paul had four substances:
citric acid
copper sulphate
indigestion tablet
sugar
He dissolved 1 g of each substance in 20 cm3 of distilled water.
He used universal indicator to find the pH of each solution.
(a)
(i)
Sugar solution does not change the colour of green universal indicator.
What does this tell you about sugar solution?
Tick the correct box.
It is an acid.
It is an alkali.
It is neutral.
It is sweet.
1 mark
(ii)
Suggest the pH of citric acid.
............
1 mark
(iii)
Indigestion tablets neutralise acid in the stomach.
What does this tell you about indigestion tablets?
...............................................................................................................
1 mark
(b)
Complete the flow chart below with the names of the substances in the boxes.
citric acid
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copper sulphate
indigestion tablet
sugar
16
Does the substance dissolve in
water to form a blue solution?
yes
no
Does it turn
universal indicator
red?
yes
no
Does it turn
universal indicator
blue?
yes
no
3 marks
maximum 6 marks
Barnard Castle School
17
12.
A science teacher showed her class three experiments, A, B and C.
The experiments and the word equations for the reactions that took place are shown below.
All the experiments were done in a fume cupboard.
experiment A
calcium
carbonate
calcium oxide forms in
the test tube
0
1
2
3
4
5
calcium
carbonate
is heated
word equation
0
1
2
3
4
5
carbon dioxide
is collected here
calcium carbonate
calcium oxide + carbon dioxide
experiment B
iron filings and sulphur
are heated together
word equation
iron + sulphur
iron sulphide
experiment C
copper
hot copper is
added to chlorine
word equation
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piece of copper covered
with brownish solid
chlorine
copper + chlorine
________________________
18
(a)
From the substances in experiments A, B and C, above, give the name of:
(i)
one metallic element;
.............................................................
1 mark
(ii)
one non-metallic element;
.............................................................
1 mark
(iii)
two compounds.
................................................... and ...................................................
1 mark
(b)
In experiment B, the iron filings weighed 2.0 g at the beginning of the experiment and the
iron sulphide produced weighed 2.8 g.
Explain this increase in mass.
.........................................................................................................................
.........................................................................................................................
1 mark
(c)
Complete the word equation for the chemical reaction in experiment C.
copper + chlorine  .............................................................
1 mark
maximum 5 marks
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19
13.
The diagram shows part of the Periodic Table.
period
0
1
H
I
II
III
IV
V
VI VII He
2
Li
Be
B
C
N
O
F
Ne
3
Na Mg
Al
Si
P
S
Cl
Ar
Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
Kr
4
5
(a)
K
Ca Sc
Ti
V
Y
Zr
Nb Mo Tc Ru Rh Pd Ag Cd In
Rb Sr
Sn Sb Te
I
Xe
Calcium burns brightly in oxygen, forming calcium oxide (CaO).
Calcium oxide reacts with water, forming a compound with the formula Ca(OH)2.
(i)
Give the name of the compound with the formula Ca(OH)2.
…………………………………………………………………………………
1 mark
(ii)
The compound, Ca(OH)2, is slightly soluble in water.
Would you expect this solution to be acidic, alkaline or neutral?
……………………………………
1 mark
(b)
The table below gives information about four compounds.
The molecules of each compound contain an atom of hydrogen and an atom of
an element from group VII of the Periodic Table. The amount of energy needed to
pull the two atoms apart is called the bond strength.
compound
name
formula
hydrogen
HF
fluride
hydrogen
HCl
chloride
hydrogen
HBr
bromide
hydrogen
HI
iodide
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bond strength
in Kj/mol
action of heat on
the compound
570
stable
432
fairly stable
366
some bromine formed
298
20
14. Use the valency information you have been given to work out he chemical formulae of the compounds
listed (i) to (vi).
I.
II.
Sodium bromide
Potassium hydroxide
III.
Silver chloride
IV.
Barium chloride
V.
VI.
Magnesium hydroxide
Iron(III) oxide
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