Global Reserves & Potable Water (AQA GCSE Chemistry)

Exam Questions

2 hours20 questions
1a1 mark

Humans use the Earth's resources to survive everyday life.

Which of the following do we not obtain from the Earth's resources.

Tick (✓) one box.

Shelter

 

Sunlight

 

Warmth

 

Food

 

Transport

 

1b4 marks

In addition to the natural resources available, humans have developed synthetic products. Sort the following items into the correct columns in Table 1.

  • Rubber

  • Ceramics

  • Poly(ethene)

  • Wood

Table 1

Natural resources

Synthetic products

 

 

 

 

 

 

1c2 marks

Table 2 shows some of Earth's natural resources and the time taken for them to form.

Table 2

Natural resource

Time taken to form in years

Wood

2 to 30

Cereal grains

0.5

Crude oil

6 x 107

Which one of the natural resources is said to be a finite resource? Explain your answer.

1d3 marks

It is becoming increasingly more important for chemists to design processes and materials that are sustainable.

Complete the sentence using words from the box.

current previous compromising
future allowing

Sustainable development meets the needs of ____________________ generations without ____________________ the ability of ____________________ generations to meet their own needs.

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2a1 mark

Water can be made potable by treating water from lakes and rivers.

What does potable water mean?

2b1 mark

The first stage in treating water from rivers and likes removes solid particles such as soil, twigs and small pebbles.

What is the name of the process used in this stage?

2c1 mark

Another stage of water treatment is to sterilise the water.

What could not be used to sterilise the water?

Tick (✓) one box.

Fluoride

 

Chlorine

 

Ozone

 

Ultraviolet light

 

2d3 marks

Sea water can be made safe to drink by desalination.

Distillation can be used to desalinate sea water.

The equipment that could be used to desalinate sea water is shown in Figure 1.

Figure 1

aqa-gcse-10-1e-tq2d-distillation-of-sea-water

Give the names of the components A to E.

Label

Name

A

 

B

 

C

 

D

 

E

 

2e1 mark

Desalination of sea water is an expensive process so it is only used to produce large quantities of drinking water when there is no alternative supply.

Give one reason why the process is so expensive?

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3a1 mark

Water samples can be analysed in the laboratory to measure pH and the amount of dissolved solids.

pH of the water samples can be determined using either a pH meter or universal indicator.

Give one reason why using a pH meter is the preferred method.

3b1 mark

A student analysed four water samples to find the pH and the amount of dissolved solids in each water sample.

They used a pH meter to find the pH and the method below to find the amount of dissolved solids.

  • Weigh an empty evaporating basin

  • Pour 20 cm3 of a sample of water into the basin

  • Heat the basin gently over a Bunsen burner until the majority of water has evaporated

  • Leave until all the water has evaporated

  • Reweigh the evaporating basin containing the dissolved solids in

How could the student calculate the amount of dissolved solids in 20 cm3 of water using the results obtained from this method?

3c3 marks

The results obtained from the analysis of the four water samples are shown in Table 1.

Table 1

Water sample

pH

Mass of dissolved solids in 20 cm3 of water / g

A

8.2

0.72

B

4.2

0.03

C

7.0

0.00

D

6.3

0.02

The student knew that sample D was tap water taken from the laboratory.

Draw one line from each of the other water samples, A, B and C, to the source of the water sample.

Use the results from the analysis shown in Table 1.

zsb-jGdS_watersamples
3d
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1 mark

What mass of dissolved solid would be present in a 100 cm3 sample of water sample B?

Tick (✓) one box.

0.03 g

 

0.15 g

 

0.30 g

 

1.50 g

 

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41 mark

There are many steps involved when treating water.

Which of the answers below is the incorrect reason for the treatment step being carried out?

 

Treatment

Explanation

A

filtration

to remove dissolved solids

B

desalination

to remove salt

C

reverse osmosis

to remove salt

D

sterilisation

to kill bacteria 

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    5a1 mark

    The Earth's resources of copper ore are limited.

    New processes to extract copper from low-grade ores have been developed.

    What is meant by the term 'low-grade ores'?

    Tick (✓) one box.

    The copper produced from these ores does not have a high economical value

     

    They contain very low percentages of copper compounds

     

    The copper they contain is impure

     

    5b2 marks

    Phytomining and bioleaching are two processes that have been developed that can extract copper from low-grade ores.

    Draw one line from each method of extraction to the substance that is used to extract copper.

    6Msbp3lO_phyto-and-bioleaching
    5c3 marks

    Complete the sentences about phytomining and bioleaching.

    Choose the correct words from the box below.

    ash an unreactive metal sediment
    leachate electrolysis copper oxide

    Phytomining results in the production of ____________________ that contains metal compounds.

    Bioleaching produces ____________________ solutions that contain metal compounds.

    The metal compounds produced can be processed further to obtain the metal, for example, copper can be extracted from copper compounds by displacement by scrap iron or ____________________.

    5d1 mark

    Phytomining and bioleaching reduce the need to mine for copper-rich ores.

    Give one disadvantage of mining.

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    61 mark

    The amount of chlorine used in swimming pools has to be carefully monitored to ensure levels don't get too high. 

    What is the reason for this?

    • It is flammable

    • It is corrosive

    • It is toxic

    • It is a diuretic 

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    7a2 marks

    Domestic uses and industrial processes produce vast quantities of waste water which must be treated before being released into the environment.

    Which two substances need to be removed from sewage and agricultural waste water?

    Tick (✓) two boxes.

    Fluoride

     

    Harmful microbes

     

    Dissolved salts

     

    Organic matter

     

    7b2 marks

    Which two substances need to be removed from industrial waste water?

    Tick (✓) two boxes.

    Harmful chemicals

     

    Harmful microbes

     

    Sodium ions

     

    Organic matter

     

    7c4 marks

    Sewage needs several stages of treatment. Figure 1 shows these different stages.

    Label the processes A and B and the names of the two substances produced by sedimentation X and Y.

    Use words from the box below.

    aerobic sludge effluent screening            anaerobic                     sterilisation

    Figure 1

    aqa-gcse-10-1e-tq4c-sewage-treatment-flowchart

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    1a6 marks

    Figure 1 shows a typical greenhouse used to generate heat for growing small batches of fruit and vegetables. 

    Figure 1 

    aqa-gcse-10-1m-q1a-greenhouse

    The frame can be made either from wood or aluminium.

    The table below provides some relevant information about both wood and aluminium.

     

    Aluminium

    Wood

    Raw material

    Non-renewable

    Renewable

    Useful lifetime in years

    50

    20

    Mass of frame in kg

    2

    80

    End of useful life

    Can be recycled

    Can be used as fuel

    Use the information to evaluate the use of wood and aluminium for making greenhouse frames.

    1b2 marks

    Making greenhouse frames from recycled aluminium is more sustainable than from aluminium extracted from aluminium ore.

    Give two reasons why this is the case. 

    1c2 marks

    The windows used in greenhouses can be made from either glass or polymers.

    The table below provides some relevant information about both these materials.

     

    Polymer

    Glass

    Cost in £ per m2

    28

    20

    Density in g / cm3

    1.2

    2.8

    Effect of sunlight

    Loses colour over time

    No effect

    Use the information from the table to suggest and explain one advantage of using polymer windows rather than glass windows.

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    2a2 marks

    Water from a local lake in the UK is used to provide drinking water to a local community.

    The water requires treatment before being suitable for consumption.

    What are the two main steps used to treat lake water?

    In your answer provide a reason for each step.

    2b3 marks

    Explain why producing drinking water from waste water is more complicated than it is to produce it from water in lakes.

    2c1 mark

    Water that is safe to drink is called potable water.

    Potable water is not pure water.

    State the difference between potable water and pure water.

    2d2 marks

    Some countries produce drinking water from sea water but this is a costly enterprise.

    Explain why producing water from sea water is so expensive.

    2e2 marks

    State how the water produced from sea water could be tested to show that it was pure.

    Give the expected results if the water was pure.

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    2 marks

    A student used the following method to find out how much solid was dissolved in a sample of sea water:

    • Measure the mass of an empty evaporating basin

    • Measure 20 cm3 of the sea water sample using a measuring cylinder and pour into the evaporating basin

    • Heat the evaporating basin on a tripod and gauze using a Bunsen burner until the solids start to form and the majority of water has evaporated

    • Leave the basin until all of the water has evaporated

    • Measure the mass of the cooled evaporating basin 

    The results the student obtained are:

    • Mass of empty evaporating basin = 21.35 g

    • Mass of evaporating basin and dry solid residue = 21.96 g

    Calculate the mass of solid dissolved in 1000 cm3 of the sea water.

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    31 mark

    During the treatment of waste water, a liquid called effluent is produced. Which process does it undergo?

    • Sedimentation

    • Anaerobic digestion

    • Screening

    • Aerobic digestion

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    1 mark

    A student was investigating the mass of dissolved solids in spring water.

    The student carried out the following steps:

    • Measure the mass of an empty evaporating basin

    • Add 50 cm3 of spring water

    • Heat up the water sample until it evaporates

    • Reweigh the evaporating basin containing the solid

    The following results were recorded:

    • Mass of empty evaporating basin = 19.56 g

    • Mass of evaporating basin and dry solid residue = 20.23 g

    What is the mass of solid dissolved in 1 dm3 of the spring water?

    • 0.67 g

    • 13.4 g

    • 33.5 g

    • 67.0 g

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    5a2 marks

    This question is about the extraction and use of metals.

    Many everyday domestic and industrial items are made from iron.

    Haematite is an ore of iron and contains the compound iron oxide, Fe2O3.

    Explain the meaning of the term ore.

    5b1 mark

    Iron is produced by reacting Fe2O3 with carbon inside a blast furnace.

    What type of reaction takes place?

    5c2 marks

    The word equation for this reaction is:

    iron oxide      +       carbon        →        iron    +    carbon dioxide

    Complete and balance the symbol equation below.

    ___Fe2O3          +          ___C           →     __________   +      __________

    5d3 marks

    Figure 1 shows the ways in which iron is extracted, used and recycled. 

    Figure 1

    aqa-gcse-10-1m-q3d-metal-recycling-flow-chart

    Explain why the recycling of iron is necessary for sustainable development. 

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    6a3 marks

    This question is about alternative methods of extraction of copper.

    Copper has many uses but is largely used in the production of electrical wiring.

    Phytomining and bioleaching are alternative methods of extracting metals like copper.

    Explain why alternative methods are necessary, commenting on how they affect the sustainability of extracting copper.

    6b4 marks

    Phytomining is the technique used to obtain copper from areas of land that contain very low percentages of copper compounds.

    Describe the process of phytomining.

    6c5 marks

    Bioleaching is another technique used to extract copper from low grade ores.

    Describe the process of bioleaching.

    6d1 mark

    State one disadvantage of these alternative methods compared to the traditional methods of metal extraction.

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    71 mark

    Copper can be extracted from low grade ores using bioleaching. 

    A leachate solution is produced.

    Which process is used to extract the copper from the leachate solution?

    • Distillation

    • Cracking

    • Displacement

    • Fermentation

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    1 mark

    A student carried out a number of chemical tests on a sample of water to determine whether it contained sodium chloride. 

    Which sample contained sodium chloride? 

     

    Flame test colour

    Add sodium hydroxide solution

    Add nitric acid and silver chloride solution

    Add hydrochloric acid and barium chloride 

    A

    brick red

    no reaction

    yellow precipitate 

    no reaction

    B

    yellow

    no reaction

     white precipitate

    no reaction

    C

    yellow

    no reaction

    cream precipitate 

    no reaction

    D

    no colour

    green precipitate

    no reaction

    white precipitate 

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      1a4 marks

      It is becoming increasingly more important for chemists to develop manufacturing processes sustainably.

      Explain what is meant by sustainable development and how chemists play a role in sustainable development.

      Include an example in your answer.

      1b6 marks

      Carrier bags are often made from poly(ethene) but chemists have developed bags that can be made from other materials including one made from corn starch.

      Table 1 shows some information about the bags made from these materials.

      Table 1

       

      Bags made from poly(ethene)

      Bags made from corn starch

      Raw material

      Crude oil

      Plants

      Energy demand during production

      Moderate

      High

      Biodegradable

      No

      Yes

      Recyclable

      Yes

      Limited

      Evaluate the use of poly(ethene) and corn starch to make carrier bags, commenting on the sustainability of the production and disposal of both types of bags.

      Use the information in Table 1 and your understanding of LCAs to help you answer.

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      2a1 mark

      In the UK, potable water is produced from fresh water.

      Lakes and rivers are common sources of fresh water.

      Name another source of fresh water.

      2b4 marks

      Explain how drinking water is obtained from fresh water.

      2c2 marks

      Pure water can be obtained from sea water by the process of distillation.

      Explain why this is not used in the UK to produce drinking water.

      2d3 marks

      Reverse osmosis is another method of desalination of fresh water which is a process that uses a membrane as shown in Figure 1.

      Figure 1

      ts-NORqP_reverse-osmosis

      Suggest what the role of the membrane is in reverse osmosis and why this is an expensive process.

      Use Figure 1 to help you answer.

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      3a6 marks

      Potable water contains dissolved solids which are not harmful to drink in small quantities.

      Describe a method that could be used to find out the amount of dissolved salts contained in different water samples.

      3b3 marks

      A student investigated the amount of dissolved solids contained in different water samples.

      They also measured the pH of the water samples.

      Their results are shown in Table 1.

      Table 1

      Water

      pH

      Mass of dissolved solid in g/dm3

      Tap water

      6.6

      0.4

      Sea water

      7.9

      28.0

      Tap water from area affected by acid rain

      5.9

      0.6

      What would you expect the pH and mass of dissolved solids to be in a sample of pure water?

      Explain your answer.

      3c2 marks

      How could the student confirm that the final water sample is pure?

      3d2 marks

      Calculate the mass of the dissolved solids in 100 cm3 of sea water?

      Use the results in Table 1.

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      4a2 marks

      Waste water, including sewage and agricultural waste water, requires treatment before being released into the environment.

      Name two substances that must be removed from waste water prior to it being released.

      4b2 marks

      Treatment of waste water produces liquid effluent and solid sewage sludge.

      What two processes does waste water go through in order to produce the effluent and sludge?

      4c2 marks

      How are the sewage sludge and liquid effluent treated?

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      3 marks

      Table 1 shows some information about how the treated solid sludge was disposed from one sewage treatment plant in 2000 and 2020.

      Table 1

      Year

      Mass of treated solid sludge in tonnes

      Used as fertiliser

      Sent to landfill

      Other

      Total

      2000

      56

      22

      55

      132

      2020

      152

      2

      39

      193

      Calculate the percentage of treated solid sludge that was sent to landfill in 2000.

      Give your answer to 3 significant figures.

      4e3 marks

      The total mass of treated solid sludge increased from 2000 to 2020 and the proportions of how the sludge was disposed of changed.

      Suggest one reason for the increase in the total mass of treated solid sludge and two reasons for the changes in the proportions of the disposal methods .

      Use Table 1 to help you answer.

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      5a2 marks

      Copper is extracted from copper ores. The traditional method of extracting copper is by quarrying and then heating in a furnace.

      In recent years, copper is being extracted from ores that contain a lower percentage of copper compounds.

      Suggest two reasons why.

      5b3 marks

      Bioleaching is a new method that can be used to extract copper from land that contains low percentages of copper compounds.

      Bioleaching uses bacteria to produce copper sulfate solution.

      Copper can be obtained from copper sulfate solution by electrolysis.

      Give another method of how copper can be obtained from copper sulfate solution and explain why this method can extract copper from its compound.

      5c6 marks

      Phytomining is another biological method to extract copper from low-grade copper ores.

      Land where copper ore has been mined contains very low percentages of copper compounds.

      Plants are grown on this land, absorbing the copper compounds through their roots.

      The process of phytomining is shown in Figure 1.

      Figure 1

      aqa-gcse-10-1h-tq5c-phytomining


      Use the information in Figure 1 and your knowledge to evaluate the method of phytomining and the traditional method to extract copper.

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