Name: C10 USING RESOURCES. Class: Question Practice. Date: 183 minutes. Time: 179 marks. Marks: HIGHER TIER. Comments: Page 1 of 67

Transcription

1 C0 USING RESOURCES Question Practice Name: Class: Date: Time: 83 minutes Marks: 79 marks Comments: HIGHER TIER Page of 67

2 C 6 H 34 C 2 H 4 + C 8 H 8 () (a) The hydrocarbon C 6 H 34 can be cracked. Balance the equation for cracking C 6 H 34 (b) Describe the differences between cracking and distillation. (2) (c) What type of reaction is cracking? Tick one box. Combustion Decomposition Neutralisation Precipitation () Page 2 of 67

3 (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 a paper bag. Plastic bag Paper bag Raw materials Crude oil or natural gas Wood Energy used in MJ.5.7 Mass of solid waste in g 4 50 Mass of CO 2 produced in kg Volume of fresh water used in dm A company stated: A Life Cycle Assessment shows that using plastic bags has less environmental impact than using paper bags. Evaluate this statement. Use your knowledge and the information from above the table above. (6) (Total 0 marks) Page 3 of 67

4 2 Rainwater is collected from the roofs of houses as shown in Figure. Figure (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 () Page 4 of 67

5 (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 () (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. (2) Page 5 of 67

6 (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 of the concrete. Figure 3 Use values from Figure 3 to describe the relationship shown by the graph. (2) (Total 6 marks) Page 6 of 67

7 3 All life on Earth depends on water. The figure below shows an iceberg floating on the sea. Gibas DigiPhoto/iStock/Thinkstock (a) Explain how the water molecules in the iceberg could end up as water in a lake. (4) Page 7 of 67

8 (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. (4) (Total 8 marks) 4 Where copper ore has been mined there are areas of land that contain very low percentages of copper 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 sulfate solution, as shown in Figure. Figure (a) (i) Complete the sentence. Using plants to extract metals is called. () Page 8 of 67

9 CuO + C + CO 2 (2) (ii) Suggest two reasons why copper from these areas of land is not extracted by smelting. (2) (iii) Complete and balance the chemical equation for the reaction of copper oxide with carbon. (b) Copper is produced from copper sulfate solution by displacement using scrap iron or by electrolysis. (i) Use the Chemistry Data Sheet to help you to answer this question. Give two reasons why scrap iron is used to displace copper. (2) Page 9 of 67

10 (ii) Figure 2 shows the electrolysis of copper sulfate solution. Figure 2 Describe what happens to the copper ions during electrolysis. (2) (Total 9 marks) Page 0 of 67

11 5 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. (4) (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? () Page of 67

12 (ii) Suggest why water filters used in the home contain particles of silver. () (c) Pure water can be produced by distillation. Why is distillation not usually an economic method of treating water for drinking? () (d) Drinking hard water has health benefits. State one health benefit of drinking hard water. () (Total 8 marks) 6 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. distillation. Pure water can be obtained from sea water by filtration. neutralisation. () (ii) What is the boiling point of pure water? C () Page 2 of 67

13 (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 cm 3 of sea water? () (ii) How could the student check that all of the water had evaporated? (2) (iii) The results the student obtained using 25 cm 3 of sea water are: mass of empty evaporating basin = 23.2 g mass of evaporating basin and dry solid residue = g Calculate the mass of solid dissolved in 000 cm 3 of the sea water. Mass dissolved in 000 cm 3 = g (2) (c) In many countries chlorine is added to drinking water supplies. Why is chlorine added to drinking water? () Page 3 of 67

14 (d) In this question you will be assessed on using good English, organising information clearly and 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, 2 and 3 show some of the results obtained. Page 4 of 67

15 Evaluate the advantages and disadvantages of adding fluoride ions to drinking water. You should support your answer with evidence from all three graphs. (6) (Total 4 marks) Page 5 of 67

16 7 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. (2) (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. () Page 6 of 67

17 (ii) The reaction in the furnace could cause environmental pollution. Explain how. (2) (iii) The extraction of pure copper is expensive. Give one reason why. () (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. (2) (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? () (Total 9 marks) Page 7 of 67

18 2Fe 2 O 3 + C Fe + CO 2 () 8 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. () (ii) Balance the symbol equation for this reaction. Page 8 of 67

19 (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 0 Iron oxide 65 Silicon dioxide 25 (i) 00 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? Answer = % () (ii) Apart from the solids shown in the table, name one other substance that would be in the 'red mud'. () Page 9 of 67

20 (iii) The purification of the aluminium oxide is usually done near to the bauxite quarries. Suggest one reason why. () (c) Aluminium is used to make many things including cans. During one year in the USA: 00 billion aluminium cans were sold 55 billion aluminium cans were recycled. Give one environmental impact of recycling aluminium cans and one ethical or social impact of recycling aluminium cans. Environmental Ethical or social (2) (Total 7 marks) Page 20 of 67

21 9 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 metal in the ore % of metal in the Earth s crust aluminium bauxite aluminium oxide, Al 2 O copper chalcocite copper sulfide, Cu 2 S iron haematite iron oxide, Fe 2 O (a) Use the information in the table and your knowledge and understanding to help you to answer the questions. (i) Suggest why purifying the copper ore produces large quantities of waste. () (ii) Suggest why the annual world production of iron is forty times greater than that of aluminium. () Page 2 of 67

22 (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. () (ii) In this electrolysis, aluminium and oxygen gas are produced from the aluminium oxide. Use the information in the diagram to suggest why most of the waste gas is carbon dioxide and not oxygen. (2) (iii) Aluminium is the most abundant metal in the Earth s crust. Suggest two reasons why we should recycle aluminium drinks cans.. 2. (2) (Total 7 marks) Page 22 of 67

23 0 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 treated with chlorine. (2) Page 23 of 67

24 (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 0.0 mg of arsenic 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 Skill level of technician Highly skilled where test is done Little training needed Laboratory only Anywhere Time to prepare the instrument for the test 5 minutes 0 seconds Sensitivity of the instrument mg of arsenic per litre of water 0. mg of arsenic per litre of water (i) Use the information in the table to give two advantages and one disadvantage of using the Portable Instrumental Method compared with the Laboratory Instrumental Method. (3) Page 24 of 67

25 (ii) The information about these two instrumental methods was provided by the Professional Institute of Water Engineers (PIWE). The Institute has no connection with the companies that make these instruments. Suggest why many people would accept the views of PIWE rather than the views of the companies that make the instruments. () (Total 6 marks) Copper can be produced from copper(ii) sulfate solution by two different methods. Method Electrolysis (a) To produce copper by electrolysis a student has inert electrodes, a d.c. power supply, a switch and electrical wires for the external circuit. Draw and label the apparatus set up to produce copper from copper(ii) sulfate solution by electrolysis. (2) (b) Suggest why the colour of the copper(ii) sulfate solution fades during the electrolysis. (3) (c) Explain how copper is produced from copper(ii) sulfate solution by electrolysis. (4) Page 25 of 67

26 Method 2 Displacement (d) The chemical equation for the displacement of copper using iron is: CuSO 4 + Fe Cu + FeSO 4 Calculate the minimum mass of iron needed to displace all of the copper from 50 cm 3 of copper(ii) sulfate solution. The concentration of the copper(ii) sulfate solution is 80 g CuSO 4 per dm 3. Relative atomic masses (A r ): O = 6; S = 32; Fe = 56; Cu = 63.5 Give your answer to 2 significant figures. Mass of iron = g (4) (Total 3 marks) 2 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 carbon monoxide. Iron ore contains iron oxide (Fe 2 O 3 ). Write a balanced equation for the reaction of iron oxide with carbon monoxide. (3) (b) Explain why this reaction is a redox reaction. (2) Page 26 of 67

27 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. (4) Page 27 of 67

28 (d) Figure shows an electromagnet being used to lift a car in a scrapyard. Figure 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. (2) Page 28 of 67

29 (e) In a scrapyard, an electromagnet is used to lift and release cars so they can be moved around. 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. (4) (Total 5 marks) 3 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 Page 29 of 67

30 (a) What is the original source of energy for tidal power schemes? () (b) Explain two advantages of using undersea tidal turbines to generate electricity rather than burning fossil fuels. (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 MJ per kg. Wood chip from willow trees has an energy value of 3 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 land would be needed to grow the willow? Amount of land needed = hectares (3) Page 30 of 67

31 (d) The table below shows the carbon dioxide emissions of four fuels used to generate electricity. Fuel Direct CO 2 emissions in kg per MWh Lifecycle CO 2 emissions in kg per MWh Coal Natural gas Oil Wood Direct CO 2 emissions are the amounts of carbon dioxide released when the fuel is burned. Lifecycle CO 2 emissions is the total amount of carbon dioxide released during all stages from 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 carbon dioxide emitting fuel. (2) (Total 0 marks) Page 3 of 67

32 4 Read the information about production of copper. World demand for copper in 204 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 by burning fossil fuels. Air is blown through the hot copper sulfide to produce copper and sulfur dioxide. Some copper is extracted from low-grade ores by phytomining. Phytomining uses plants to absorb 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. (Total 6 marks) Page 32 of 67

33 5 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: Cu 2 S(s) + O 2 (g) 2 Cu(s) + SO 2 (g) Explain why there would be an environmental problem if sulfur dioxide gas escaped into the atmosphere. (2) (b) The impure copper produced by smelting is purified by electrolysis, as shown below. Copper atoms are oxidised at the positive electrode to Cu 2+ ions, as shown in the half equation. Cu(s) Cu 2+ (aq) + 2e (i) How does the half equation show that copper atoms are oxidised? () Page 33 of 67

34 (ii) The Cu 2+ ions are attracted to the negative electrode, where they are reduced to produce copper atoms. Write a balanced half equation for the reaction at the negative electrode. () (iii) Suggest a suitable electrolyte for the electrolysis. () (c) Copper metal is used in electrical appliances. Describe the bonding in a metal, and explain why metals conduct electricity. (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. (3) Page 34 of 67

35 (e) A compound in a copper ore has the following percentage composition by mass: 55.6% copper, 6.4% iron, 28.0% sulfur. Calculate the empirical formula of the compound. Relative atomic masses (A r ): S = 32; Fe = 56; Cu = 63.5 You must show all of your working. Empirical formula = (4) (Total 6 marks) Page 35 of 67

36 6 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 % pure copper by electrolysis. Use values from the graph to explain why copper is purified to %. (2) Page 36 of 67

37 (b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Read the information in the box. Copper extraction World demand for copper for the year 20 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 + O 2 Cu + SO 2 A scientist made the statement: Copper should be recycled. Use the information in the box and your own knowledge and understanding to justify the scientist s statement. Page 37 of 67

38 Extra space (6) (c) Phytomining is used to obtain copper from land that contains very low percentages of copper compounds. Describe how copper compounds are obtained by phytomining. (3) (Total marks) Page 38 of 67

39 7 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 empty bottles are returned to be re-used. Glass milk bottles are re-used 24 times on average. The glass to make new milk bottles is produced when a mixture of sand, limestone, soda and recycled glass is heated to about 600 C in a furnace. There are 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 is used up the empty bottles are discarded as waste. The plastic used to make these milk bottles is poly(ethene). Poly(ethene) is produced from crude oil by first using fractional distillation, then cracking the naphtha fraction and finally polymerising the ethene. About 5% of used poly(ethene) is recycled. The new plastic milk bags contain 2 litres of milk. The milk bags are also made from poly(ethene). A milk bag uses 75% less poly(ethene) than is used to make the poly(ethene) milk bottles. When the milk is used up the empty bags are discarded as waste. (a) Describe what happens in fractional distillation so that fractions, such as naphtha, are separated from crude oil. (3) Page 39 of 67

40 (b) Supermarkets claim that using milk bags instead of milk bottles would have less environmental impact. Do you agree with this claim? Use the information in the article and your knowledge and understanding to make appropriate comparisons to justify your answer. (4) (Total 7 marks) Page 40 of 67

41 8 Supermarkets in the UK have been advised by the Government to stop giving plastic bags to customers. The Government states that this is because plastic bags use up resources that are not 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 with large numbers of used plastic bags. Method Reused Recycled Burned Dumped Description of what happens to the plastic bag used again by the customer collected, transported, washed and melted to make new plastic items collected, transported and burnt to release heat energy mixed with other household waste, collected, transported and disposed of at a landfill site Use the information and your knowledge and understanding to briefly give one advantage and one disadvantage for each of these methods. Reused Recycled Burned Dumped (4) (Total 4 marks) Page 4 of 67

42 9 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 and untreated. It is estimated that 2.2 million people die each year as a result of drinking contaminated water. DADA DANESHANANDA, Man with filtered water from the Mafi-Zongo water project. Efforts are being made to solve this problem and more water is being treated. Describe how water in the United Kingdom is treated. Explain how this makes it safe to drink. (Total 3 marks) Page 42 of 67

43 20 The Mary Rose was a wooden warship. The Mary Rose sank in 545 but was lifted from the sea bed in 982. 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 have been used to make the poles to support the Mary Rose. Material Density in g / cm 3 Relative strength Cost in per kg Steel Titanium 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 Advantage 2 Disadvantage (3) (ii) The preserving process used titanium poles. Tick ( ) one other property of titanium which made titanium a suitable choice for the poles. Page 43 of 67

44 Property Tick ( ) Electrical insulator High resistance to corrosion Shiny () (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 Gold Iron Electrolysis of molten compound Mined as the pure metal from the ground 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. () (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. () Page 44 of 67

45 (ii) 88% of a bronze alloy is copper. What percentage of the alloy is tin? Percentage of tin = % () (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 () (Total 0 marks) Page 45 of 67

46 Mark schemes (a) 4 (C 2 H 4 ) (b) (c) (d) cracking involves a catalyst distillation does not or distillation does not involve a chemical change but cracking does Decomposition Level 3 (5 6 marks): A logically structured evaluation with links involving several comparisons. Nearly all points made are relevant and correct. Level 2 (3 4 marks): Some valid comparisons made between the two types of bag. There may be some incorrect or irrelevant points. Level ( 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 / incomplete 6 [0] 2 (a) Safe to drink Page 46 of 67

47 (b) To remove undissolved solids (c) the gas is chlorine / Cl 2 (d) which sterilises water as distance between steel increases strength of concrete decreases change above and change below.0 cm separation is compared and described must refer to graph values for this mark [6] 3 (a) Level 2 (3 4 marks): A detailed and coherent explanation of how the water molecules transfer through the water cycle from one form / area to another. Logical links are made between the general details of the water cycle to the context of the iceberg. Level ( 2 marks): Simple relevant facts stated about the water cycle. Details may be missing and any links made with the context of the iceberg may be inconsistent or vague. 0 marks: No relevant content. (b) 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 solid materials removed by filtration or by passing through filter beds microbes 4 are killed by sterilisation allow killed by chlorine / ozone / ultraviolet light [8] Page 47 of 67

48 4 (a) (i) phytomining (ii) (the land contains) very little copper allow low grade ore or large amounts of waste ignore quarrying / benefits of using plants (iii) uneconomical accept (smelting) uses a lot of energy / fossil fuels allow expensive Cu 2 CuO + C 2 Cu + CO 2 allow 2 CuO + C Cu 2 + CO 2 for mark (b) (i) iron is more reactive (than copper) iron is cheap(er than copper) allow cheaper or uses less energy than electrolysis (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 [9] Page 48 of 67

49 5 (a) filter to remove solids or insoluble particles OR add coagulant () flocculation / settling / remove solids () (add) chlorine accept ozone / UV to reduce the number of microbes accept to kill microbes / bacteria / germs accept sterilise allow disinfect ignore remove microbes (b) (i) ion exchange resin allow ion exchange column allow sodium ions / Na + allow hydrogen ions / H + (ii) prevent growth of microbes accept sterilise accept to kill microbes / bacteria / germs accept to reduce the number of microbes ignore remove microbes (c) high cost of energy / heating allow uses a lot of energy (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 [8] 6 (a) (i) distillation Page 49 of 67

50 (ii) 00 / one hundred (b) (i) measuring cylinder or pipette or burette allow phonetic spelling do not accept teat pipette ignore any additional words or volumes (ii) (iii) (re)heat the evaporating basin accept heat to constant mass for 2 marks weigh (again) or mass will not change if no other mark awarded allow mark for a chemical test for water 33.2 (g) correct answer with or without working scores 2 marks allow mass of residue = (24.04 g 23.2 g) = 0.83 for mark allow ecf (mass of residue 40) for mark 2 (c) to kill microbes / bacteria or to sterilise / disinfect water allow to prevent disease ignore to make it safe to drink Page 50 of 67

51 (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 refer to the information on page 4, and apply a best fit approach to the marking. 0 marks No relevant content Level ( 2 marks) A simple relevant comment has been made on the data from at least one of the graphs. 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 shows) fluoride ions reduce the amount of tooth decay (graph shows) the effect in reducing tooth decay is greatest for year olds accept any in range (graph 2 shows) the fluoride ions reduce percentage with decayed teeth (graph 2 shows) effect is greatest at 2.5 to 3 mg per 000 g of water then decay increases if more than 2.5 to 3 mg of fluoride ions per 000 g water accept any in range (graph 2 shows percentage) decay decreases from 0 to 2.5 / 3 mg per 000 g (graph 3 shows) more marked / brittle teeth as fluoride level increases above points linked together to draw a justified conclusion 6 [4] 7 (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 marks 2 Page 5 of 67

52 allow (sulfur reacts with oxygen to) produce sulfur dioxide / SO 2 (b) (i) large amounts / 98% of rock to dispose of as waste accept contains toxic (metal) compounds / bioleacher or waste rock takes up a lot of space (ii) (copper sulfide reacts with oxygen to) produce sulfur dioxide / SO 2 that causes acid rain allow description of effects of acid rain or sulfur dioxide if no other mark awarded allow CO 2 produced which causes global warming or CO 2 produced by burning fuel or heating the furnace for mark (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 (iv) allow ores contain a low percentage of copper (copper ions move towards) the negative electrode / cathode (v) because copper ions / Cu 2+ are positively charged or are oppositely charged or copper ions need to gain electrons allow because metal ions are positive or opposites attract (growing) plants [9] 8 (a) (i) reduction (ii) accept redox / smelting Page 52 of 67

53 (b) (i) 55 ignore other units (ii) (iii) Water accept sodium hydroxide accept correct formulae H 2 O or NaOH any one from: save energy / fuel for transporting the ore accept less (cost of) transport allow transported quickly (old) quarries nearby for waste/red mud (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 produced Ethical or social any one from: saves resources allow using resources more than once creates (local) employment if answers reversed and both correct award mark more people aware of the need for recycling allow less qualified noise pollution if not given in environmental [7] 9 (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 or nearly 00% waste in the ore ignore reference to percentage of metal in the Earth's crust or energy used or pollution Page 53 of 67

54 (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 of metal in ore iron is stronger ignore harder cheaper / costs less easier to extract (b) (i) has melting point lower than 950 C (it = aluminium) allow has a low melting point ignore boiling point (ii) (iii) electrode(s) made of carbon oxygen reacts with electrode(s) / carbon accept C + O 2 ( CO 2 ) NB oxygen reacts with the carbon electrode(s) = 2 marks 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 recycle 2 [7] Page 54 of 67

55 0 (a) filtered: removes insoluble / solid Ignore named substances / minerals do not accept ions chlorine: kills microorganisms / microbes / bacteria / disinfects (water) allow kills germs / pathogens or sterilises allow chlorine is a disinfectant ignore cleans water or removes impurities / bacteria (b) (i) advantages of portable: accept converse throughout any two from : costs less little training needed water can be tested within 0 seconds / immediately / quicker can be used anywhere 2 disadvantage of portable less precise / sensitive allow only detect down to 0. mg ignore less accurate (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 products [6] (a) electrodes connected to d.c. power supply by wires for this diagram ignore the material used for the electrodes as long as they are made from carbon or metals that are inert electrodes labelled anode (+) and cathode ( ) Page 55 of 67

56 (b) (c) copper ions cause the blue colour answer must be in terms on copper ions copper ions are reduced / converted to copper ions so the concentration of copper ions decreased if no other mark awarded allow mark for copper ions are used up during electrolysis copper ions are positive so are attracted to the inert cathode or inert negative electrode copper ions gain electrons at the inert cathode or inert negative electrode so they are reduced to form copper atoms (d) 50 cm 3 contains 4 g CuSO 4 M r CuSO 4 = g CuSO 4 reacts with 56 g Fe =.40(43877) =.4 (g) accept.4(g) with no working shown for 4 marks allow.40(43887) without working shown for 3 marks [3] 2 (a) Fe 2 O CO 2Fe + 3 CO 2 correct formulae of reactants correct formulae of products correct balancing (b) iron loses oxygen reduction carbon gains oxygen oxidation Page 56 of 67

57 (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 coil correct directional arrows (e) any two from: mark for suggestion, mark for correctly linked explanation use many coils or tight coils or long wire () to give a strong magnetic field for lifting heavy objects () explanation must be correctly linked to the suggestion to gain the mark 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 [5] 3 (a) gravity (of moon and sun) Page 57 of 67

58 (b) any two from: mark for statement, mark for correctly linked reason tidal energy is renewable () so won t run out like fossil fuels () 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 (c) (d) doesn t produce particulates so less effect on health / environment coal consumption per year = million = MJ hectare of willow will produce = MJ per year so need = (hectares) allow with no working shown for 3 marks although has higher direct emissions than other fuels Max. 4 it has much lower lifetime emissions [0] Page 58 of 67

59 4 Level 3 (5 6 marks): A detailed, coherent and logical justification of the scientist s statement, with relevant links made between statements in the question, phytomining and the effects of other methods of metal production 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 ( 2 marks): Discrete relevant points made. The logic may be unclear and may not be consistent with the reasoning. 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] 5 (a) because sulfur dioxide causes acid rain which kills fish / aquatic life or dissolves / damages statues / stonework or kills / stunts growth of trees if no other mark awarded then award mark for sulfur dioxide is toxic or causes breathing difficulties. (b) (i) electrons are lost (ii) (iii) Cu e Cu allow Cu 2+ Cu 2e ignore state symbols copper sulfate allow any ionic copper compound Page 59 of 67

60 (c) (d) (lattice of) positive ions delocalised electrons accept sea of electrons (electrostatic) attraction between the positive ions and the electrons 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 between oppositely charged ions then do not award M or M3 MAX 2 (copper compounds are absorbed / taken up by) plants allow crops which are burned the ash contains the copper compounds do not award M3 if the ash contains copper (metal) (e) / A r 55.6 / / / 32 moles ratio 3 3 formula Cu 3 FeS 3 award 4 marks for Cu 3 FeS 3 with some correct working award 3 marks for Cu 3 FeS 3 with no working if the answer is not Cu 3 FeS 3 award up to 3 marks for correct steps from the table apply ecf if the student has inverted the fractions award 3 marks for an answer of CuFe 3 S 4 [6] Page 60 of 67

61 6 (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 than impure copper) scores or answers quoting a conductivity value from the graph scores 2 Page 6 of 67

62 (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 marks No relevant content Level ( 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 not recycling or the advantage of recycling. Answers such as less fossil fuel needed so less carbon dioxide produced or less carbon dioxide produced so less global warming examples of the points made in the response resources (recycling) conserves supplies of ores copper 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 energy less fuel used at a lower cost land pollution mining scars landscape or produces noise pollution mining 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 (c) atmospheric pollution burning fossil fuels produces carbon dioxide / greenhouse gas which (may) cause global warming or climate change extraction produces sulfur dioxide which causes acid rain which can kill trees / fish grow plants then plants are burned accept plants absorb copper (through roots) 6 ash (from burning) contains copper compounds [] Page 62 of 67

63 7 (a) allow answers referring specifically to the naphtha fraction crude oil is evaporated/vaporised (by heating) the vapours are condensed (by cooling) (fractions condense) / boil at different temperatures allow fractions have different boiling points Page 63 of 67

64 (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 / glass milk bottle) allow produces less greenhouse gases / causes less global warming allow produces less CO 2 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 whereas glass bottles can be re-used poly(ethene) points 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 uses a limited raw material / crude oil whereas the raw materials for glass 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 whereas recycled glass is used to make new bottles 4 [7] Page 64 of 67

65 8 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 waste Recycled saves raw materials / crude oil saves energy / use of fuel has to be collected / transported / washed / separated / melted reduces carbon / CO 2 emissions reduces use of landfill can be used for new products ignore uses energy Burned heat / energy released can be used (for heating / generating electricity) has to be collected / transported reduces use of landfill wastes the resource / plastic releases harmful gases / toxic gases / CO 2 Page 65 of 67

66 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 cause explosions (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 above [4] 9 two methods and linked explanation or method and two explanations, linked = 3 marks no linking of method and explanation then max 2 marks ignore references to removal of hardness method : filter ignore screening / sedimentation explanation : remove insoluble substances / remove solids / small bits / dirt / mud/ soil / sand / silt 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 [3] Page 66 of 67

67 20 (a) (i) (advantages of titanium) ignore references to figures less dense allow lighter stronger ignore references to corrosion (disadvantage of titanium) (ii) more expensive high resistance to corrosion (b) Metal Method of extraction extra line from any metal negates mark (c) silver ignore chemical symbols (d) (i) mixture (ii) 2 (%) (iii) plants [0] Page 67 of 67