1.
Ammonium sulfate and ammonium nitrate are both fertilisers.
Ammonium sulfate has the formula (NH4)2SO4.
Ammonium nitrate has the formula NH4NO3.
(a)
What is the total number of atoms shown in the formula (NH4)2SO4?
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[1]
(b)
Ammonium nitrate has a relative formula mass (Mr) of 80.
What is the relative formula mass of ammonium sulfate?
The relative atomic mass of H is 1, of N is 14, of O is 16, and of S is 32.
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relative formula mass = ..................................................
[1]
Ammonium nitrate contains 35% by mass of nitrogen.
What is the percentage by mass of nitrogen in ammonium sulfate?
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percentage by mass = ...................................................
[1]
(c)
Ammonium sulfate dissolves in water.
Why is it important that a fertiliser dissolves in water?
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(d)
Clare makes ammonium nitrate.
Look at the apparatus she uses.
acid
25.0 cm3 ammonia
She uses 25.0 cm3 of an alkali called ammonia.
She slowly adds an acid until the alkali is just neutralised.
(i)
What is the name of the acid she must use?
Choose from the list.
hydrochloric acid
nitric acid
phosphoric acid
sulfuric acid
answer .................................................................................................
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(ii)
The pH value in the beaker changes as the acid is added.
Describe how the pH value changes.
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Explain why.
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[2]
(iii)
Clare makes 0.45 g of ammonium nitrate.
She predicts she should make 0.50 g.
What is her percentage yield?
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percentage yield = ................................................ %
[2]
[Total 9 marks]
2.
Jack investigates some reactions of dilute sulfuric acid.
(a)
Jack adds some sodium hydroxide solution to dilute sulfuric acid.
Sodium hydroxide is an alkali.
The pH value of the acid increases as the sodium hydroxide is added.
(i)
Explain why the pH value increases.
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(ii)
A salt is made when sodium hydroxide reacts with dilute sulfuric acid.
What is the name of this salt?
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[1]
(b)
Jack also uses the internet to investigate sulfuric acid, H2SO4.
He finds out that dilute sulfuric acid contains ions.
One of these is the sulphate ion, SO42–.
Write down the name or formula of another ion found in dilute sulfuric acid.
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[1]
[Total 3 marks]
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3.
This question is about the reactions of acids.
(a)
Look at the diagram. It shows the apparatus used to neutralise an acid with an
alkali.
alkali
acid
The alkali is added to the acid.
The pH number of the solution increases.
Explain why.
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[1]
(b)
Calcium carbonate reacts with hydrochloric acid.
A salt called calcium chloride is made.
Calcium carbonate also reacts with nitric acid.
Write down the name of the salt that is made.
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(c)
Copper oxide, CuO, neutralises hydrochloric acid, HCl.
Copper chloride, CuCl2, and water are made.
(i)
What type of substance is copper oxide?
Choose from the list.
allotrope
base
fertiliser
salt
answer .....................................................
[1]
(ii)
Write a balanced symbol equation for this reaction.
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[2]
[Total 5 marks]
4.
This question is about chemical calculations.
(a)
Calcium hydroxide has the formula Ca(OH)2.
Calculate the relative formula mass (Mr) of calcium hydroxide.
(The relative atomic mass (Ar) for Ca = 40, for O = 16 and for H = 1.)
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answer .....................................................
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(b)
Calcium carbonate reacts with hydrochloric acid.
Calcium chloride, carbon dioxide and water are made.
Look at the symbol equation for the reaction.
CaCO3 + 2HCl → CaCl2 + CO2 + H2O
Calculate the mass of calcium chloride, CaCl2, that can be made from 50 g of
calcium carbonate, CaCO3.
(The relative atomic mass (Ar) for Ca = 40, for C = 12, for O = 16, for H = 1 and
for Cl = 35.5.)
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answer .....................................................
[2]
[Total 3 marks]
5.
Natalie enjoys gardening.
She uses the internet to find out about fertilisers.
She finds out that ammonium nitrate, NH4NO3, improves leaf and stem growth.
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(a)
Ammonium nitrate can be made by reacting an alkali with an acid.
(i)
What is the name of the alkali needed?
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[1]
(ii)
What is the name of the acid needed?
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[1]
(b)
Natalie finds out that potassium chloride can also be used as a fertiliser.
Potassium chloride can be made by reacting potassium carbonate with
hydrochloric acid.
Balance the symbol equation for this reaction.
K2CO3
+
HCl
→
KCl
+
CO2
+
H2O
[1]
(c)
Natalie makes some potassium chloride.
She uses 2.76 g of potassium carbonate.
She predicts she should make 1.49 g of potassium chloride.
(i)
Natalie actually makes 0.596 g of potassium chloride.
What is her percentage yield?
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percentage yield = ..................................%
[2]
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(ii)
In another experiment, Natalie uses less potassium carbonate.
This time she uses 1.38 g of potassium carbonate.
How much potassium chloride does she predict she will make?
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predicted mass of potassium chloride made = .................................. g
[1]
(d)
Natalie also finds out that there are problems when farmers use too much
fertiliser.
One problem is called eutrophication.
Write about eutrophication.
Your answer should include
• how it happens
• the effect of eutrophication.
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[3]
[Total 9 marks]
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6.
This question is about the manufacture of chemicals.
(a)
Many millions of tonnes of ammonia are manufactured each year in the United
Kingdom.
Ammonia is made by the reaction of nitrogen and hydrogen in a continuous
process.
The conditions used for this reaction are
•
450 °C
•
high pressure
•
iron catalyst.
Explain why these conditions are chosen.
Use ideas about rate of reaction and percentage yield in your answer.
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(b)
A new anti-cancer drug is made from a rare plant only found in South America.
Less than 100 kg of the drug is made each year.
It is made in a batch process.
The cost of manufacturing and developing the drug is very high.
Write about some of the reasons why this cost is very high.
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(c)
The anti-cancer drug is made in a batch process rather than a continuous one.
Suggest one reason why.
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[Total 6 marks]
7.
Washing up liquids contain a detergent.
Washing up liquid will clean plates covered in fat.
(a)
Look at the diagram of a detergent molecule.
Label the diagram to show
•
the hydrophilic part of the molecule
•
the hydrophobic part of the molecule.
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(b)
Detergent molecules help to remove fat from a dirty plate.
Explain how.
A labelled diagram will help you to answer this question.
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[2]
[Total 3 marks]
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8.
Julie works for a drugs company.
She is making a new medicine to treat heart disease.
(a)
One of the chemicals needed to make the medicine is extracted from a plant.
Describe one way chemicals can be extracted from plants.
Your answer should include
•
•
•
what is done to the plant
how the chemical is removed
how the chemical is purified.
You may wish to draw a diagram.
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(b)
A new medicine is expensive to develop.
Research and development costs contribute to the high costs of medicines.
Explain how.
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[Total 4 marks]
9.
Diamond and graphite have different properties and different uses.
Look at the table.
It shows some information about the properties of diamond and graphite.
property
diamond
graphite
state at room temperature
solid
solid
colourless, clear and lustrous
dull black
melting point
very high
very high
hardness
very hard
soft
solubility in water
insoluble
insoluble
does not conduct
good conductor
appearance at room
temperature
electrical conductivity
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(a)
Diamond is used in jewellery.
This is because diamond is colourless, clear and lustrous.
Diamond is also used to make cutting tools.
Write about two properties of diamond that make it suitable for cutting tools.
Use the table to help you.
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[2]
(b)
Look at the structures of diamond and graphite.
= carbon atom
strong bond
strong bond
weak bond
diamond
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(i)
Diamond and graphite both have very high melting points.
Explain why.
Use ideas about their structure.
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[1]
(ii)
Graphite conducts electricity.
Explain why.
Use ideas about its structure.
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[Total 4 marks]
10.
This question is about drinking water.
(a)
Water purification has three processes.
They are filtration, sedimentation and chlorination.
Complete the table to explain why each process is used.
Sedimentation has been done for you.
process
filtration
why it is used
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sedimentation
chlorination
It allows very small solid particles to settle out.
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[2]
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(b)
Drinking water can be made by the distillation of sea water.
Look at the diagram. It shows the distillation of sea water.
sea water
drinking water
HEAT
The distillation of sea water to make drinking water is an expensive process.
Explain why.
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(c)
Drinking water sometimes contains chloride ions.
Silver nitrate reacts with sodium chloride.
Sodium nitrate and silver chloride are made.
Write a word equation for this reaction.
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[1]
[Total 4 marks]
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