name: c10 using resources - immanuel college...c10 using resources question practice name: _____...

C10 USING RESOURCESQuestion Practice

Name: ________________________

Class: ________________________

Date: ________________________

Time: 183 minutes

Marks: 179 marks

Comments: HIGHER TIER

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(a) The hydrocarbon C16H34 can be cracked.

Balance the equation for cracking C16H34

C16H34 → ________________ C2H4 + C8H18

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(b) Describe the differences between cracking and distillation.

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(2)

(c) What type of reaction is cracking?

Tick one box.

Combustion

Decomposition

Neutralisation

Precipitation

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(d) Ethene is used to make poly(ethene).

Poly(ethene) is used to make plastic bags.

the table below shows data from a Life Cycle Assessment (LCA) for a plastic bag and apaper bag.

Plastic bag Paper bag

Raw materials Crude oil or natural gas Wood

Energy used in MJ 1.5 1.7

Mass of solid waste in g 14 50

Mass of CO2 produced in kg 0.23 0.53

Volume of fresh water used in dm3 255 4 520

A company stated: ‘A Life Cycle Assessment shows that using plastic bags has lessenvironmental impact than using paper bags’.

Evaluate this statement. Use your knowledge and the information from above the tableabove.

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(Total 10 marks)

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Rainwater is collected from the roofs of houses as shown in Figure 1.

Figure 1

(a) The water in the storage tank is not potable.

What does potable mean?

Tick one box.

Contains dissolved substances

Pure

Safe to drink

Tastes nice

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(b) Why should the water in the tank be filtered to make it potable?

Tick one box.

To kill microbes

To remove dissolved gases

To remove dissolved solids

To remove undissolved solids

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(c) A gas which bleaches litmus paper can be added to the water to make it potable.

Name this gas and explain why it is added.

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(d) The storage tank is made from concrete reinforced with steel wire, as shown in Figure 2.

Figure 2.

Figure 3 shows how the distance between the steel wires affects the relative strength ofthe concrete.

Figure 3

Use values from Figure 3 to describe the relationship shown by the graph.

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(2)

(Total 6 marks)

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All life on Earth depends on water.

The figure below shows an iceberg floating on the sea.

© Gibas DigiPhoto/iStock/Thinkstock

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(a) Explain how the water molecules in the iceberg could end up as water in a lake.

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(b) Rainwater collects in rivers and lakes.

Water in rivers and lakes contains materials that make the water unsafe to drink.

Describe how the water from rivers and lakes is treated to make it safe to drink.

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(4)

(Total 8 marks)

Where copper ore has been mined there are areas of land that contain very low percentages ofcopper compounds.

One way to extract the copper is to grow plants on the land.

The plants absorb copper compounds through their roots.

The plants are burned to produce copper oxide.

The copper oxide produced from plants can be reacted to produce copper or copper sulfatesolution, as shown in Figure 1.

Figure 1

(a) (i) Complete the sentence.

Using plants to extract metals is called _______________________ .

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(ii) Suggest two reasons why copper from these areas of land is not extracted bysmelting.

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(2)

(iii) Complete and balance the chemical equation for the reaction of copper oxide withcarbon.

____CuO + C __________________ + CO2

(2)

(b) Copper is produced from copper sulfate solution by displacement using scrap iron or byelectrolysis.

(i) Use the Chemistry Data Sheet to help you to answer this question.

Give two reasons why scrap iron is used to displace copper.

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(ii) Figure 2 shows the electrolysis of copper sulfate solution.

Figure 2

Describe what happens to the copper ions during electrolysis.

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(2)

(Total 9 marks)

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Water in Britain is taken from reservoirs to use as drinking water.

© KatieJonesPhotography/iStock/Thinkstock

(a) What are the two main steps used to treat water from reservoirs?

Give one reason for each step.

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(b) Some people use water filters to treat water before drinking it.

(i) Water filters remove hardness from hard water.

What is in water filters that removes hardness from water?

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(ii) Suggest why water filters used in the home contain particles of silver.

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(c) Pure water can be produced by distillation.

Why is distillation not usually an economic method of treating water for drinking?

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(d) Drinking hard water has health benefits.

State one health benefit of drinking hard water.

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(1)

(Total 8 marks)

Most water contains dissolved compounds.

The concentrations of these dissolved compounds are higher in sea water than in drinking water.

(a) (i) Draw a ring around the correct answer to complete the sentence.

Pure water can be obtained from sea water by

distillation.

filtration.

neutralisation.

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(ii) What is the boiling point of pure water? __________________ °C

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(b) A student wanted to find out how much solid was dissolved in sea water.

This is the method the student used:

• measure the mass of an empty evaporating basin• measure 25 cm 3 of sea water and pour it into the evaporating basin• heat the evaporating basin gently until all of the water has evaporated• measure the mass of the evaporating basin containing the solid residue.

(i) What piece of apparatus would be suitable for measuring 25 cm3 of sea water?

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(ii) How could the student check that all of the water had evaporated?

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(iii) The results the student obtained using 25 cm3 of sea water are:

mass of empty evaporating basin = 23.21 g mass of evaporating basin and dry solid residue = 24.04 g

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

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Mass dissolved in 1000 cm3 = ______________ g

(2)

(c) In many countries chlorine is added to drinking water supplies.

Why is chlorine added to drinking water?

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(d) In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Compounds containing fluoride ions are added to some drinking water supplies.

Many scientists have done research into the effects of fluoride ions in drinking water.

Graphs 1, 2 and 3 show some of the results obtained.

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Evaluate the advantages and disadvantages of adding fluoride ions to drinking water.

You should support your answer with evidence from all three graphs.

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(Total 14 marks)

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Metals are extracted from their ores.

Many copper ores contain only 2% of copper compounds.

(a) Copper is now extracted from ores containing a low percentage of copper compounds.

Suggest two reasons why.

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(b) Chalcocite, an ore of copper, contains copper sulfide.

The flow diagram shows how copper metal is extracted from chalcocite.

(i) Suggest one reason why it is difficult to dispose of the waste rock.

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(ii) The reaction in the furnace could cause environmental pollution.Explain how.

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(iii) The extraction of pure copper is expensive.Give one reason why.

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(iv) Pure copper is produced by electrolysis of copper sulfate solution.

Which electrode do the copper ions move towards?Give a reason for your answer.

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(v) Large areas of land are contaminated with copper compounds.Phytomining can be used to remove these copper compounds from the land.

What is used in phytomining to remove copper compounds from the land?

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(1)

(Total 9 marks)

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Cans for food and drinks are made from steel or aluminium.The main metal in steel is iron.

By Sun Ladder (Own work) [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons

(a) Iron is extracted by heating a mixture of iron oxide and carbon in a blast furnace.

(i) Name this type of reaction.

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(ii) Balance the symbol equation for this reaction.

2Fe2O3 + ______ C → ______ Fe + ______ CO2

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(b) Aluminium ore, bauxite, contains aluminium oxide, iron oxide and silicon dioxide.Aluminium is extracted by electrolysis of aluminium oxide.

The 'red mud' which is dumped in very large ponds contains:

Name of solid Percentage (%)

Aluminium oxide 10

Iron oxide 65

Silicon dioxide 25

(i) 100 tonnes of bauxite produced 50 tonnes of pure aluminium oxide and 50 tonnes of'red mud'.

What percentage of aluminium oxide did the bauxite contain?

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Answer = _____________________ %

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(ii) Apart from the solids shown in the table, name one other substance that would be inthe 'red mud'.

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(iii) The purification of the aluminium oxide is usually done near to the bauxite quarries.

Suggest one reason why.

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(c) Aluminium is used to make many things including cans.

During one year in the USA:

• 100 billion aluminium cans were sold

• 55 billion aluminium cans were recycled.

Give one environmental impact of recycling aluminium cans and one ethical or socialimpact of recycling aluminium cans.

Environmental _______________________________________________________

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Ethical or social ______________________________________________________

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(Total 7 marks)

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The flow diagram shows the main stages used to extract a metal from its ore.

mining the ore → purifying the ore → extracting the metal

The table shows some information about three metals.

Metal Metal ore Purified ore% of metalin the ore

% of metal in theEarth’s crust

aluminium bauxite aluminium oxide, Al2O3 28.0 8.0

copper chalcocite copper sulfide, Cu2S 0.5 0.001

iron haematite iron oxide, Fe2O3 29.0 5.0

(a) Use the information in the table and your knowledge and understanding to help you toanswer the questions.

(i) Suggest why purifying the copper ore produces large quantities of waste.

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(ii) Suggest why the annual world production of iron is forty times greater than that ofaluminium.

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(b) Aluminium is used for drinks cans.Aluminium is extracted from its purified ore by electrolysis.

(i) Suggest why the aluminium produced in the electrolysis cell is a liquid.

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(ii) In this electrolysis, aluminium and oxygen gas are produced from the aluminiumoxide.

Use the information in the diagram to suggest why most of the waste gas is carbondioxide and not oxygen.

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(iii) Aluminium is the most abundant metal in the Earth’s crust.

Suggest two reasons why we should recycle aluminium drinks cans.

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2. ____________________________________________________________

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(2)

(Total 7 marks)

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Good quality water is essential for life.

(a) In the United Kingdom, water is filtered and treated with chlorine to make it safe to drink.

Explain why the water is:

filtered _____________________________________________________________

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treated with chlorine. __________________________________________________

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(b) Millions of people in Bangladesh drink water from wells that contain high levels of arsenic.Arsenic is poisonous.

The World Health Organisation recommends that there should be no more than 0.01 mg ofarsenic per litre in drinking water.

The table gives some information about two instrumental methods of testing for arsenic.

Factor to consider Laboratory Instrumental Method Portable Instrumental Method

Cost of equipment £10 000 £50

Skill level oftechnician

Highly skilled where test is done

Little training needed Laboratory only Anywhere

Time to prepare theinstrument for the test

5 minutes 10 seconds

Sensitivity of theinstrument

0.000001 mg of arsenic per litreof water

0.1 mg of arsenic per litreof water

(i) Use the information in the table to give two advantages and one disadvantage ofusing the Portable Instrumental Method compared with the Laboratory InstrumentalMethod.

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(ii) The information about these two instrumental methods was provided by theProfessional Institute of Water Engineers (PIWE). The Institute has no connectionwith the companies that make these instruments.

Suggest why many people would accept the views of PIWE rather than the views ofthe companies that make the instruments.

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(1)

(Total 6 marks)

Copper can be produced from copper(II) sulfate solution by two different methods.

Method 1 – Electrolysis

(a) To produce copper by electrolysis a student has inert electrodes, a d.c. power supply, aswitch and electrical wires for the external circuit.

Draw and label the apparatus set up to produce copper from copper(II) sulfate solution byelectrolysis.

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(b) Suggest why the colour of the copper(II) sulfate solution fades during the electrolysis.

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(c) Explain how copper is produced from copper(II) sulfate solution by electrolysis.

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Method 2 – Displacement

(d) The chemical equation for the displacement of copper using iron is:

CuSO4 + Fe Cu + FeSO4

Calculate the minimum mass of iron needed to displace all of the copper from 50 cm3 ofcopper(II) sulfate solution.

The concentration of the copper(II) sulfate solution is 80 g CuSO4 per dm3.

Relative atomic masses (Ar): O = 16; S = 32; Fe = 56; Cu = 63.5

Give your answer to 2 significant figures.

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Mass of iron = __________________ g

(4)

(Total 13 marks)

Iron is a metal that has many uses.

(a) Iron is extracted from iron ore. Part of the process involves reduction of the ore with carbonmonoxide.

Iron ore contains iron oxide (Fe2O3).

Write a balanced equation for the reaction of iron oxide with carbon monoxide.

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(b) Explain why this reaction is a redox reaction.

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Steel is an alloy of iron. Steel is used to make cars.

After its useful life a car is taken to a scrapyard for recycling.

(c) Suggest four benefits of recycling a car body.

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(d) Figure 1 shows an electromagnet being used to lift a car in a scrapyard.

Figure 1

An electromagnet is made up of a solenoid.

Figure 2 shows a solenoid.

Figure 2

Draw the magnetic field of the solenoid on Figure 2.

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(e) In a scrapyard, an electromagnet is used to lift and release cars so they can be movedaround.

Suggest two ways a solenoid could be made to lift and release cars in a scrapyard.

Explain why each suggestion would be useful in the scrapyard.

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(4)

(Total 15 marks)

Electricity in the UK is generated in many ways.

The figure below shows an undersea turbine.

The undersea turbine uses tidal energy to generate electricity.

© alex-mit/iStock/Thinkstock

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(a) What is the original source of energy for tidal power schemes?

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(b) Explain two advantages of using undersea tidal turbines to generate electricity rather thanburning fossil fuels.

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(4)

(c) Some power stations burn wood instead of fossil fuels to generate electricity.

A coal-burning power station burns 6 million tonnes of coal per year.

Coal has an average energy value of 29.25 MJ per kg.

Wood chip from willow trees has an energy value of 13 MJ per kg.

A hectare of agricultural land can produce 9 tonnes of dry willow wood per year.

If this power station burned dry willow wood instead of coal, how much agricultural landwould be needed to grow the willow?

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Amount of land needed = _____________ hectares

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(d) The table below shows the carbon dioxide emissions of four fuels used to generateelectricity.

FuelDirect CO2 emissions

in kg per MWhLifecycle CO2 emissions

in kg per MWh

Coal 460 540

Natural gas 185 215

Oil 264 313

Wood 2 100 58

Direct CO2 emissions are the amounts of carbon dioxide released when the fuel isburned.

Lifecycle CO2 emissions is the total amount of carbon dioxide released during all stagesfrom fuel extraction to when the fuel has been used.

Use the data from the table above to explain why wood is considered to be a low carbondioxide emitting fuel.

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(2)

(Total 10 marks)

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Read the information about production of copper.

• World demand for copper in 2014 was about 22 million tonnes.

• World reserves of copper are about 700 million tonnes.

• Most of the copper today is obtained from copper ores. The ores are mined.

• Copper ore is heated in a furnace to produce copper sulfide. The furnace is heated byburning fossil fuels. Air is blown through the hot copper sulfide to produce copper andsulfur dioxide.

• Some copper is extracted from low-grade ores by phytomining. Phytomining uses plants toabsorb copper compounds. The plants are burned and copper is extracted from the ashes.

A scientist stated:

‘more copper should be extracted by phytomining.’

Use the information to justify the scientist’s statement.

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This question is about copper.

(a) Copper can be extracted by smelting copper-rich ores in a furnace.

The equation for one of the reactions in the smelting process is:

Cu2S(s) + O2(g) 2 Cu(s) + SO2(g)

Explain why there would be an environmental problem if sulfur dioxide gas escaped intothe atmosphere.

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(2)

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(b) The impure copper produced by smelting is purified by electrolysis, as shown below.

Copper atoms are oxidised at the positive electrode to Cu2+ ions, as shown in the halfequation.

Cu(s) Cu2+(aq) + 2e−

(i) How does the half equation show that copper atoms are oxidised?

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(ii) The Cu2+ ions are attracted to the negative electrode, where they are reduced toproduce copper atoms.

Write a balanced half equation for the reaction at the negative electrode.

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(1)

(iii) Suggest a suitable electrolyte for the electrolysis.

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(c) Copper metal is used in electrical appliances.

Describe the bonding in a metal, and explain why metals conduct electricity.

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(4)

(d) Soil near copper mines is often contaminated with low percentages of copper compounds.

Phytomining is a new way to extract copper compounds from soil.

Describe how copper compounds are extracted by phytomining.

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(e) A compound in a copper ore has the following percentage composition by mass:

55.6% copper, 16.4% iron, 28.0% sulfur.

Calculate the empirical formula of the compound.

Relative atomic masses (Ar): S = 32; Fe = 56; Cu = 63.5

You must show all of your working.

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Empirical formula = ______________________________

(4)

(Total 16 marks)

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This question is about copper.

(a) Most of the copper extracted is used in electric circuits.

The figure below shows how impurities change the electrical conductivity of copper.

Percentage of impurities in copper

Copper extracted by smelting is about 99% pure.

The 99% pure copper produced by smelting is purified to 99.9999% pure copper byelectrolysis.

Use values from the graph to explain why copper is purified to 99.9999%.

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(b) In this question you will be assessed on using good English, organising informationclearly and using specialist terms where appropriate.

Read the information in the box.

Copper extraction

World demand for copper for the year 2011 was about 20 million tonnes.

World reserves of copper are estimated to be 700 million tonnes.

Most of the copper used is obtained from copper ores, which are mined.

The copper ore chalcopyrite is heated in a furnace to produce copper sulfide, CuS

The furnace is heated by burning fossil fuels.

Air is then blown through the hot copper sulfide, to produce copper and sulfur dioxide.

CuS + O2 → Cu + SO2

A scientist made the statement: ‘Copper should be recycled’.

Use the information in the box and your own knowledge and understanding to justify thescientist’s statement.

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Extra space _________________________________________________________

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(6)

(c) Phytomining is used to obtain copper from land that contains very low percentages ofcopper compounds.

Describe how copper compounds are obtained by phytomining.

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(3)

(Total 11 marks)

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Read the article and then answer the questions.

Supermarkets launch eco-friendly plastic milk bags.Could this be the end of the milk bottle?

Milk bottles are made from glass or from plastic.

Glass milk bottles contain 0.5 litres of milk. When the milk is used up the emptybottles are returned to be re-used. Glass milk bottles are re-used 24 times onaverage. The glass to make new milk bottles is produced when a mixture of sand,limestone, soda and recycled glass is heated to about 1600 °C in a furnace. Thereare almost unlimited amounts of the raw materials needed to produce this glass.About 35% of used glass is recycled.

The most common plastic milk bottles contain 2 litres of milk. When the milk isused up the empty bottles are discarded as waste. The plastic used to make thesemilk bottles is poly(ethene). Poly(ethene) is produced from crude oil by first usingfractional distillation, then cracking the naphtha fraction and finally polymerising theethene. About 5% of used poly(ethene) is recycled.

The new plastic milk bags contain 2 litres of milk. The milk bags are also madefrom poly(ethene). A milk bag uses 75% less poly(ethene) than is used to make thepoly(ethene) milk bottles. When the milk is used up the empty bags are discarded aswaste.

(a) Describe what happens in fractional distillation so that fractions, such as naphtha, areseparated from crude oil.

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(b) Supermarkets claim that using milk bags instead of milk bottles would have lessenvironmental impact.

Do you agree with this claim?

Use the information in the article and your knowledge and understanding to makeappropriate comparisons to justify your answer.

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(Total 7 marks)

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Supermarkets in the UK have been advised by the Government to stop giving plastic bags tocustomers. The Government states that this is because plastic bags use up resources that arenot renewable and that the manufacture of plastic bags produces carbon dioxide.Most of these plastic bags are made from poly(ethene). The table shows methods to deal withlarge numbers of used plastic bags.

Method Description of what happens to the plastic bag

Reused used again by the customer

Recycled collected, transported, washed and melted to make new plastic items

Burned collected, transported and burnt to release heat energy

Dumped mixed with other household waste, collected, transported anddisposed of at a landfill site

Use the information and your knowledge and understanding to briefly give one advantage andone disadvantage for each of these methods.

Reused ________________________________________________________________

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Recycled _______________________________________________________________

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Burned ________________________________________________________________

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Dumped _______________________________________________________________

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(4)

(Total 4 marks)

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Good quality water is needed for a healthy life.

In the United Kingdom, obtaining safe water for drinking is as simple as turning on a tap.The water is made safe to drink by water companies.

However, in many parts of Africa and Asia, water used for drinking is contaminated anduntreated. It is estimated that 2.2 million people die each year as a result of drinkingcontaminated water.

DADA DANESHANANDA, Man with filtered water from the

Mafi-Zongo water project. www.amurt.net/africa/ghana/2005

Efforts are being made to solve this problem and more water is being treated.

Describe how water in the United Kingdom is treated.

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Explain how this makes it safe to drink.

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The Mary Rose was a wooden warship. The Mary Rose sank in 1545 but was lifted from the seabed in 1982. Scientists are now preserving the ship.

The image shows the Mary Rose being supported on poles. As part of the preservation process,the ship was sprayed with water for a long time.

By Mary Rose Trust (MR Trust) [CC BY-SA 3.0] via Wikimedia Commons

(a) (i) The table below gives information about two materials. These materials could havebeen used to make the poles to support the Mary Rose.

Material Density in g / cm3 Relative strength Cost in £ per kg

Steel 7.85 1 4

Titanium 4.51 3.9 4000

Give two advantages and one disadvantage of using titanium rather than steel.

Use only the information from the table above to answer this question.

Advantage 1 ___________________________________________________

Advantage 2 ___________________________________________________

Disadvantage __________________________________________________

(3)

(ii) The preserving process used titanium poles.

Tick (✔) one other property of titanium which made titanium a suitable choice for thepoles.

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Property Tick (✔✔✔✔)

Electrical insulator

High resistance to corrosion

Shiny

(1)

(b) Some metal objects found on the Mary Rose were made of gold or iron.

Draw one line from each metal to its usual method of extraction.

Metal Method of extraction

Electrolysis of molten

compound

Gold

Mined as the pure metal

from the ground

Iron

Reduction of metal oxide

with carbon

(2)

(c) Another metal found on the Mary Rose has the chemical symbol Ag.

Name the metal with the chemical symbol Ag.

Use the Chemistry Data Sheet to help you answer this question.

___________________________________________________________________

(1)

(d) The Mary Rose had bronze cannons.

Bronze is an alloy made from two metals, copper and tin.

(i) Use the correct answer from the box to complete the sentence.

compound mixture polymer

An alloy is a ____________________________ of metals.

(1)

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(ii) 88% of a bronze alloy is copper. What percentage of the alloy is tin?

______________________________________________________________

Percentage of tin = ________ %

(1)

(iii) Phytomining is used to extract copper from the ground.

What are used in phytomining?

Draw a ring around the correct answer.

bacteria fossils plants

(1)

(Total 10 marks)

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Mark schemes

(a) 4 (C2H4)11

(b) cracking involves a catalyst1

distillation does not

or

distillation does not involve a chemical change

but cracking does1

(c) Decomposition1

(d) Level 3 (5–6 marks):A logically structured evaluation with links involving several comparisons. Nearly all pointsmade are relevant and correct.

Level 2 (3–4 marks):Some valid comparisons made between the two types of bag. There may be someincorrect or irrelevant points.

Level 1 (1–2 marks):A vague response with few correct and relevant points and with no direct comparisons.

0 marks:No relevant content

Indicative content

Accept converse in terms of plastic bags for all statements• Paper bags are made from a renewable resource• Plastic bags are made from a finite resource• Paper bags require more energy to manufacture• Paper bags produce more waste• Paper bags are biodegradable• Paper bags create more CO 2

• CO 2 created by paper bags offset by photosynthesis in growing wood• Paper bag requires much more fresh water• Paper bags cannot be recycled• Agree because non-renewability less important than other factors or disagree

because of converse or can’t say because data inconclusive / incomplete6

[10]

(a) Safe to drink12

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(b) To remove undissolved solids1

(c) the gas is chlorine / Cl21

which sterilises water1

(d) as distance between steel increases strength of concrete decreases1

change above and change below 1.0 cm separation is compared and described

must refer to graph values for this mark1

[6]

(a) Level 2 (3–4 marks):A detailed and coherent explanation of how the water molecules transfer through thewater cycle from one form / area to another. Logical links are made between the generaldetails of the water cycle to the context of the iceberg.

Level 1 (1–2 marks):Simple relevant facts stated about the water cycle. Details may be missing and any linksmade with the context of the iceberg may be inconsistent or vague.

0 marks:No relevant content.

Indicative content• water in the iceberg is in its solid state• when the iceberg melts water is in its liquid form• and the water molecules go into the sea• water evaporates from the surface of the sea• so the water molecules go into the air as vapour• as the air rises it cools• so water vapour condenses into droplets in clouds• clouds can be moved around the world by winds• droplets then fall as rain / snow / hail / precipitation• into a lake

4

3

(b) solid materials1

removed by filtration or by passing through filter beds1

microbes1

are killed by sterilisation1

allow killed by chlorine / ozone / ultraviolet light

[8]

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(a) (i) phytomining14

(ii) (the land contains) very little copper

allow low grade ore or large amounts of waste

ignore quarrying / benefits of using plants

1

uneconomical

accept (smelting) uses a lot of energy / fossil fuels

allow expensive1

(iii) Cu1

2 CuO + C ➔ 2 Cu + CO2

allow 2 CuO + C ➔ Cu2 + CO2 for 1 mark1

(b) (i) iron is more reactive (than copper)1

iron is cheap(er than copper)

allow cheaper or uses less energy than electrolysis1

(ii) any two from:• copper / ions move or are attracted to the negative electrode / cathode• where they are reduced or gain (two) electrons• where they form copper (metal / atoms)

2

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(a) filter1

to remove solids or insoluble particles

OR

add coagulant (1)

flocculation / settling / remove solids (1)1

(add) chlorine

accept ozone / UV1

to reduce the number of microbes

accept to kill microbes / bacteria / germs

accept sterilise

allow disinfect

ignore remove microbes1

(b) (i) ion exchange resin

allow ion exchange column

allow sodium ions / Na+

allow hydrogen ions / H+

1

(ii) prevent growth of microbes

accept sterilise

accept to kill microbes / bacteria / germs

accept to reduce the number of microbes

ignore remove microbes1

(c) high cost of energy / heating

allow uses a lot of energy1

(d) any one from:• helps to develop / maintain bones

allow any suitable positive effect on bones• helps to develop / maintain teeth

allow any suitable positive effect on teeth• reduces heart disease

1

[8]

5

(a) (i) distillation16

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(ii) 100 / one hundred1

(b) (i) measuring cylinder or pipette or burette

allow phonetic spelling

do not accept teat pipette

ignore any additional words or volumes1

(ii) (re)heat the evaporating basin

accept heat to constant mass for 2 marks1

weigh (again) or mass will not change

if no other mark awarded allow 1 mark for a chemical test for water1

(iii) 33.2 (g)

correct answer with or without working scores 2 marks

allow mass of residue = (24.04 g − 23.21 g) = 0.83 for 1 mark

allow ecf (mass of residue × 40) for 1 mark2

(c) to kill microbes / bacteria or to sterilise / disinfect water

allow to prevent disease

ignore ‘to make it safe to drink’1

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(d) Marks awarded for this answer will be determined by the Quality of Communication(QoC) as well as the standard of the scientific response. Examiners should also referto the information on page 4, and apply a ‘best−fit’ approach to the marking.

0 marksNo relevant content

Level 1 (1 − 2 marks)A simple relevant comment has been made on the data from at least one of thegraphs.

Level 2 (3 − 4 marks)At least two of the graphs have been considered with a relevant comment made.

Level 3 (5 − 6 marks)All the graphs have been considered and relevant comments made about each.A justified conclusion may be given.

examples of chemistry points made in the response:

extra information

• (graph 1 shows) fluoride ions reduce the amount of tooth decay• (graph 1 shows) the effect in reducing tooth decay is greatest for 55−64 year olds

accept any in range 55 − 64• (graph 2 shows) the fluoride ions reduce percentage with decayed teeth• (graph 2 shows) effect is greatest at 2.5 to 3 mg per 1000 g of water then decay

increases if more than 2.5 to 3 mg of fluoride ions per 1000 g water

accept any in range 2.5 − 3• (graph 2 shows percentage) decay decreases from 0 to 2.5 / 3 mg per 1000 g• (graph 3 shows) more marked / brittle teeth as fluoride level increases• above points linked together to draw a justified conclusion

6

[14]

(a) any two from:

• copper / ores are running out / harder to find

• there are no / very small amounts of high-grade copper ores left

• copper metal is in demand

• copper is expensive

• now economical to extract copper from low-grade ores

it = copper

allow new methods of extraction e.g. bioleaching and phytomining

allow high-grade ores are running out for 2 marks2

7

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(b) (i) large amounts / 98% of rock to dispose of as waste

accept contains toxic (metal) compounds / bioleacher

orwaste rock takes up a lot of space

1

(ii) (copper sulfide reacts with oxygen to) produce sulfur dioxide / SO2

allow (sulfur reacts with oxygen to) produce sulfur dioxide / SO21

that causes acid rain

allow description of effects of acid rain or sulfur dioxide

if no other mark awarded allow CO2 produced which causes globalwarming or CO2 produced by burning fuel or heating the furnace for1 mark

1

(iii) any one from:

• large amounts of fuels / energy used (for the furnace and electrolysis)

allow large amounts of electricity needed

ignore high temperature / electrolysis unqualified

• (the extraction has) many steps / stages / processes

allow (extraction) is a long process / takes a lot of time

• large amounts of ore / material have to be mined

allow ores contain a low percentage of copper1

(iv) (copper ions move towards) the negative electrode / cathode1

because copper ions / Cu2+ are positively charged or are oppositely charged orcopper ions need to gain electrons

allow because metal ions are positive or opposites attract1

(v) (growing) plants1

[9]

(a) (i) reduction

accept redox / smelting1

8

(ii) 3 4 3

1

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(b) (i) 55

ignore other units

(ii) Water

accept sodium hydroxide

accept correct formulae H2O or NaOH1

(iii) any one from:

• save energy / fuel for transporting the ore

accept less (cost of) transport allow transported quickly

• (old) quarries nearby for waste/red mud1

(c) Environmental

any one from:

• less mining / quarrying (of bauxite)

allow loss of habitat / less qualified noise pollution

• less landfill space needed / used

allow less red mud / waste

• less use of fossil fuels / energy

• less carbon dioxide produced1

Ethical or social

any one from:

• saves resources

allow using resources more than once

• creates (local) employment

if answers reversed and both correct award 1 mark

• more people aware of the need for recycling

allow less qualified noise pollution if not given in environmental1

[7]

(a) (i) low percentage / very little of metal (in the ore)

accept only 0.5% metal in the ore or over 99% waste in the ore ornearly 100% waste in the ore

ignore reference to percentage of metal in the Earth's crust orenergy used or pollution

1

9

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(ii) any one from

(it = iron)

• iron uses less energy / fuel for extraction

ignore electrolysis / uses electricity / reactivity

• iron has more uses

• more demand for iron

ignore high abundance in the Earth’s crust / high percentage ofmetal in ore

• iron is stronger

ignore harder

• cheaper / costs less

• easier to extract1

(b) (i) has melting point lower than 950°C

(it = aluminium)

allow has a low melting point

ignore boiling point1

(ii) electrode(s) made of carbon1

oxygen reacts with electrode(s) / carbon

accept C + O2 (→ CO2)

NB oxygen reacts with the carbon electrode(s) = 2 marks1

(iii) any two from:

• saves resources / non-renewable

accept aluminium / ore will run out or conserves aluminium

• landfill problem

accept aluminium does not corrode

• saves energy / fuel / electricity

ignore global warming

• less carbon dioxide / carbon emissions or reduces carbon footprint

ignore consequences of quarrying / mining

• less quarrying / mining

ignore pollution / harms environment / costs / easy to recycle2

[7]

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(a) filtered: removes insoluble / solid

Ignore named substances / minerals

do not accept ions1

10

chlorine: kills microorganisms / microbes / bacteria / disinfects (water)

allow kills germs / pathogens or sterilises

allow chlorine is a disinfectant

ignore cleans water or removes impurities / bacteria1

(b) (i) advantages of portable:

accept converse throughout

any two from :

• costs less

• little training needed

• water can be tested within 10 seconds / immediately / quicker

• can be used anywhere2

disadvantage of portable

less precise / sensitive

allow only detect down to 0.1 mg

ignore less accurate1

(ii) (PIWE) is unbiased

it / they = PIWE

allow honest / trusted / respected / reliable

ignore professional / scientific / skilled

or

company may be biased

allow company trying to sell products1

[6]

(a) electrodes connected to d.c. power supply by wires

for this diagram ignore the material used for the electrodes as longas they are made from carbon or metals that are inert

1

11

electrodes labelled anode (+) and cathode (−)1

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(b) copper ions cause the blue colour

answer must be in terms on copper ions1

copper ions are reduced / converted to copper ions1

so the concentration of copper ions decreased1

if no other mark awarded allow 1 mark for copper ions are used upduring electrolysis

(c) copper ions are positive1

so are attracted to the inert cathode or inert negative electrode1

copper ions gain electrons at the inert cathode or inert negative electrode1

so they are reduced to form copper atoms1

(d) 50 cm3 contains 4 g CuSO41

Mr CuSO4 = 159.51

4 g CuSO4 reacts with × 56 g Fe

= 1.40(43877)1

= 1.4 (g)1

accept 1.4(g) with no working shown for 4 marks

allow 1.40(43887) without working shown for 3 marks

[13]

(a) Fe2O3 + 3 CO 2Fe + 3 CO2

correct formulae of reactants1

12

correct formulae of products1

correct balancing1

(b) iron loses oxygen – reduction1

carbon gains oxygen – oxidation1

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(c) any four from:

• resources for manufacture are limited• recycling reduces the use of resources• reduces energy consumption in extraction / manufacture• reduces waste from processing and extraction• reduces environmental impact of extraction

4

(d)

field lines going through and around coil1

correct directional arrows1

(e) any two from:

1 mark for suggestion, 1 mark for correctly linked explanation

• use many coils or tight coils or long wire (1)• to give a strong magnetic field for lifting heavy objects (1)

explanation must be correctly linked to the suggestion to gain themark

or• add an iron core• to increase field circuit for lifting

or• include a switch in circuit• so can drop / pick up cars

max. 4

[15]

(a) gravity (of moon and sun)113

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(b) any two from:

1 mark for statement, 1 mark for correctly linked reason

• tidal energy is renewable (1)• so won’t run out like fossil fuels (1)

or

• doesn’t emit carbon dioxide• so won’t contribute to global warming / climate change

or

• doesn’t emit oxides of sulfur or nitrogen• so doesn’t cause acid rain

or

• doesn’t use fossil fuels• so less impact on environment of extraction / transport

or

• doesn’t produce particulates• so less effect on health / environment

Max. 4

(c) coal consumption per year = 29.25 × 1000 × 6 million = 175 500 000 000 MJ1

1 hectare of willow will produce 9 × 13 × 1000 = 117 000 MJ per year1

so need 175 500 000 000 ÷ 117 000 = 1 500 000 (hectares)1

allow 1 500 000 with no working shown for 3 marks

(d) although has higher direct emissions than other fuels1

it has much lower lifetime emissions1

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Level 3 (5–6 marks):A detailed, coherent and logical justification of the scientist’s statement, with relevant links madebetween statements in the question, phytomining and the effects of other methods of metalproduction on the environment.

Level 2 (3–4 marks):An attempt to justify the scientist’s statement is made, with some attempt at linking statements.The logic may be inconsistent at times but builds towards a coherent argument.

Level 1 (1–2 marks):Discrete relevant points made. The logic may be unclear and may not be consistent with thereasoning. Links are not made.

0 marks:No relevant content

Indicative content• phytomining conserves supplies of ores• copper will be available for longer as at present rate of use copper ores will run out in

about 35 years• phytomining conserves supplies of fossil fuels or energy• less fuel used at a lower cost• mining scars landscape or produces noise pollution• mining destroys wildlife habitats• with more phytomining less need to mine ores• with phytomining less habitat destroyed or less scarring of landscape• with phytomining less need to use landfill for waste• burning fossil fuels produces carbon dioxide / greenhouse gas• burning fossil fuels causes global warming or climate change• extraction from ores produces sulfur dioxide which causes acid rain

[6]

14

(a) because sulfur dioxide causes acid rain1

which kills fish / aquatic life or dissolves / damages statues / stonework or kills /stunts growth of trees

if no other mark awarded then award 1 mark for sulfur dioxide istoxic or causes breathing difficulties.

1

15

(b) (i) electrons are lost1

(ii) Cu2+ + 2e−→ Cu

allow Cu2+→ Cu − 2e−

ignore state symbols1

(iii) copper sulfate

allow any ionic copper compound1

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(c) (lattice of) positive ions1

delocalised electrons

accept sea of electrons1

(electrostatic) attraction between the positive ions and the electrons1

electrons can move through the metal / structure or can flow

allow electrons can carry charge through the metal / structure

if wrong bonding named or described or attraction betweenoppositely charged ions then do not award M1 or M3 − MAX 2

1

(d) (copper compounds are absorbed / taken up by) plants

allow crops1

which are burned1

the ash contains the copper compounds

do not award M3 if the ash contains copper (metal)1

(e) / Ar 55.6 / 63.5 16.4 / 56 28.0 / 32

moles 0.876 0.293 0.875

ratio 3 1 3

formula Cu3FeS3

award 4 marks for Cu3FeS3 with some correct working

award 3 marks for Cu3FeS3 with no working

if the answer is not Cu3FeS3 award up to 3 marks for correct stepsfrom the table apply ecf

if the student has inverted the fractions award 3 marks for ananswer of CuFe3S

4

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(a) pure copper is twice as good a conductor as 99% pure copper

accept reverse argument

accept answers quoting 2 correct values from the graph scores 2

qualitative answer (e.g. pure copper is a better conductor thanimpure copper) scores 1

or

answers quoting a conductivity value from the graph scores 12

16

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(b) Marks awarded for this answer will be determined by the Quality of Communication(QC) as well as the standard of the scientific response.

0 marksNo relevant content

Level 1 (1–2 marks)Simple list of a limited number of points given, with no linking between ideas

Level 2 (3–4 marks)A broader set of points made. There will probably not be links between ideas

Level 3 (5–6 marks)Answer includes linking between ideas, showing the consequence of either notrecycling or the advantage of recycling. Answers such as less fossil fuel needed soless carbon dioxide produced or less carbon dioxide produced so less globalwarming

examples of the points made in the response

resources(recycling) conserves supplies of orescopper available for longer

as (at present rate of use) copper ores will run out in about 35 years(recycling) conserves supplies of fossil fuels or energyless fuel used at a lower cost

land pollutionmining scars landscape or produces noise pollutionmining destroys wildlife habitats(recycling) less need to mine ores / fossil fuels

so less habitat destroyed or less scarring of landscape(recycling) less need to use landfill for waste

atmospheric pollutionburning fossil fuels produces carbon dioxide / greenhouse gas

which (may) cause global warming or climate changeextraction produces sulfur dioxide

which causes acid rainwhich can kill trees / fish

6

(c) grow plants

accept plants absorb copper (through roots)1

then plants are burned1

ash (from burning) contains copper compounds1

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(a) allow answers referring specifically to the naphtha fraction

crude oil is evaporated/vaporised (by heating)1

17

the vapours are condensed (by cooling)1

(fractions condense) / boil at different temperatures

allow fractions have different boiling points1

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(b) any four from:

answer yes or no does not gain credit

ignore references to volume of milk held / number of bottles used /biodegradability / habitats / pollution / mining / dust

each marking point must be a comparison

milk bag points

• uses (75%) less crude oil to make (than a plastic milk bottle)

allow eg uses 75% less

poly(ethene) which is made from crude oil

• uses less energy / fuel to make (than a plastic / glass milk bottle)

• produces less carbon dioxide to manufacture (than a plastic / glassmilk bottle)

allow produces less greenhouse gases / causes less globalwarming

allow produces less CO2 on burning

• produces less waste (than a plastic / glass milk bottle)

allow takes up less landfill (space)

allow an argued case for more waste eg milk bags are discarded /cannot be reused

• less fuel used for transport than glass milk bottles

• (produces waste because) milk bags are only used once whereasglass bottles can be re-used

allow milk bags are discarded but glass bottles can be reused (24 /many times)

allow glass bottles can be reused but milk bags can’t

poly(ethene) points

• uses a limited raw material / crude oil whereas the raw materials forglass are almost unlimited

• less (5%) poly(ethene) is recycled (compared to glass (35%))

allow (35%) glass is recycled or (5%) poly(ethene) (bottles)recycled BUT milk bags aren’t / are discarded

or

recycled poly(ethene) is not used to make new bags whereasrecycled glass is used to make new bottles

4

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Reused

• saves raw materials / crude oil

• unable to reuse many times

• bags easily split

• saves energy / fuel / transport

• fewer bags needed / made

• reduces carbon / CO 2 emissions

• reduces use of landfill

• saves cost of a new bag

• no waste1

18

Recycled

• saves raw materials / crude oil

• has to be collected / transported / washed / separated /melted

• saves energy / use of fuel

• reduces carbon / CO 2 emissions


• can be used for new products

ignore uses energy1

Burned

• heat / energy released can be used (for heating / generating electricity)

• has to be collected / transported


• wastes the resource / plastic

• releases harmful gases / toxic gases / CO 21

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Dumped

• collected / transported with household waste

• wastes the resource

• plastic uses landfill

• (slowly) biodegrades or produces methane which can be used as a fuel

• produces methane which is a greenhouse gas / could causeexplosions

• (not biodegradable so) does not release CO 2 / green house gas into the air

• not biodegradable / take years to decompose

ignore cost / litter / waste / global warming / habitats unless mentioned above1

[4]

two methods and 1 linked explanation or 1 method and two explanations, 1 linked = 3 marks

no linking of method and explanation then max 2 marks

ignore references to removal of hardness

method 1:

filter

ignore screening / sedimentation

explanation 1:

remove insoluble substances / remove solids / small bits / dirt / mud/ soil / sand / silt

19

method 2:

precipitate / flocculate / add eg. alum

allow other named substances

explanation 2:

removes (some) soluble material as solids / removes (some) metal ions

method 3:

add chlorine / chlorine dioxide / ozone

explanation 3:

sterilise / kill bacteria / microorganisms / microbes

ignore ‘remove bacteria’

ignore disinfect

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(a) (i) (advantages of titanium)

ignore references to figures

less dense

allow lighter1

stronger

ignore references to corrosion1

(disadvantage of titanium)

more expensive1

(ii) high resistance to corrosion1

20

(b) Metal Method of extraction

extra line from any metal negates mark11

(c) silver

ignore chemical symbols1

(d) (i) mixture1

(ii) 12 (%)1

(iii) plants1

[10]

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name: c10 using resources - immanuel college...c10 using resources question practice name: _____...

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