Alkenes — Paper 3 · IGCSE Science - Combined 0653

8 (a) Petroleum is separated into useful fractions, as shown in Fig. 8.1. refinery gas gasoline gas oil petroleum Fig. 8.1 (i) Petroleum is a fossil fuel. Name two other fossil fuels. 1. … 2. … [1] (ii) The fractions obtained from petroleum have different uses as fuels. Draw one line from each use to the fraction from which the fuel is obtained. One line has been drawn for you. use fraction heating fuel refinery gas diesel engine fuel gasoline cooking fuel gas oil petrol engine fuel [2] (iii) When fuels burn, the reaction produces a temperature increase. State the name given to reactions that always cause a temperature increase. … [1] (b) (i) The structure of a molecule of a compound is shown below. Name this compound. H H C C H H … [1] (ii) The formula of ethanol is C2H5OH. Complete the structure of a molecule of ethanol. H C [2] (c) Petroleum is a mixture of different compounds. Methane, CH4, is a compound. (i) State what is meant by a compound. Use ideas about atoms in your answer. … … [1] (ii) Explain what is meant by a mixture. You may use ideas about separation methods in your answer. … … [1]

9 marks

Mark scheme: 8(a)(i) coal (and) natural gas ; (either order) 1 Question Answer Marks 8(a)(ii) three correct lines = 2 marks one or two correct lines = 1 mark ; 2 8(a)(iii) exothermic ; 1 8(b)(i) ethene ; 1 8(b)(ii) C-C bond correct and C-H bonds correct ; O-H correctly bonded to C ; 2 8(c)(i) atoms of more than one element joined together ; 1 8(c)(ii) different chemical substances not joined together / can be separated by (suitable named) separation technique; 1

This question in 0653/33 Oct/Nov 2018

2 (a) Petroleum is a fossil fuel. (i) State the name of one other fossil fuel. … [1] (ii) State the name of the industrial process used to separate petroleum into useful products. … [1] (iii) State one use for naptha. … [1] (b) Compound X and compound Y are obtained from petroleum. The structures of molecules of these compounds are shown in Fig. 2.1. H H H H H H H H C C C C C H C C H H H H H H H compound X compound Y Fig. 2.1 (i) Name the group of saturated hydrocarbons that includes compound X. … [1] (ii) Describe the changes, if any, that occur when compound X and compound Y are added to separate samples of aqueous bromine. compound X … … compound Y … … [3] [Total: 7]

7 marks

Mark scheme: 2(a)(i) coal / natural gas ; 1 2(a)(ii) fractional distillation ; 1 2(a)(iii) feedstock / for making chemicals ; 1 2(b)(i) alkane(s) ; 1 Question Answer Marks 2(b)(ii) (compound X) no change ; (compound Y) brown / orange (to) ; colourless / decolourises ; 3

This question in 0653/32 Feb/March 2019

5 (a) Petroleum contains hydrocarbons. These are separated into useful fractions by fractional distillation, as shown in Fig. 5.1. refinery gas gasoline naphtha gas oil petroleum bitumen Fig. 5.1 (i) Identify a fraction shown in Fig. 5.1 used for fuel in cars. … [1] (ii) Identify a fraction shown in Fig. 5.1 used for bottled gas for heating and cooking. … [1] (b) (i) Name the type of hydrocarbon which contains only single bonds. … [1] (ii) Identify the products of the complete combustion of hydrocarbons. … and … [1] (c) Compound X is made from large hydrocarbon molecules in a reaction called cracking. Compound X reacts with aqueous bromine, changing it from orange to colourless. Molecules of compound X join together to form a polymer. (i) Suggest the identity of compound X. … [1] (ii) State the type of polymerisation in which molecules of compound X form a polymer. … [1] (d) Hydrocarbon molecules contain atoms of the elements carbon and hydrogen only. (i) A carbon atom has 6 electrons. Complete Fig. 5.2 to show the electronic structure of this carbon atom. Fig. 5.2 [1] (ii) Complete the dot-and-cross diagram in Fig. 5.3 to show the covalent bond in a molecule of hydrogen gas, H2. H H Fig. 5.3 [1] (iii) State why covalent bonds, rather than ionic bonds, form between carbon atoms and hydrogen atoms. … … [1] [Total: 9]

9 marks

Mark scheme: 5(a)(i) gasoline ; 1 5(a)(ii) refinery gas ; 1 5(b)(i) alkane(s) / saturated ; 1 5(b)(ii) carbon dioxide / CO2 and water / H2O ; 1 5(c)(i) ethene / C2H4 / any named alkene / any correct alkene formula / alkene ; 1 5(c)(ii) addition (polymerisation) ; 1 5(d)(i) 2,4 arrangement ; 1 Question Answer Marks 5(d)(ii) H H 1 5(d)(iii) they / carbon and hydrogen are (both) non-metals / it is a simple molecule ; 1 X •

This question in 0653/32 May/June 2019

2 Petroleum is a mixture of compounds which are separated in a fractional distillation column. Process X changes molecules in one fraction, as shown in Fig. 2.1. fractional process X distillation column products strong heat petroleum Fig. 2.1 (a) The products of process X include alkenes. (i) Identify process X. … [1] (ii) Describe the colour change that is seen when aqueous bromine is mixed with an alkene. from … to … [2] (iii) Name the substance that is formed by the addition polymerisation of ethene. … [1] (b) Most of the compounds in petroleum are alkanes. Alkanes and alkenes contain carbon and hydrogen atoms only. (i) Name the type of compound that contains carbon and hydrogen atoms only. … [1] (ii) State the type of chemical bond that forms between carbon and hydrogen atoms. … [1] (iii) Identify the two products of the complete combustion of alkanes. … and … [2] (iv) The formula of methane is CH4. Complete the dot‑and‑cross diagram to show the shared electron pairs in a molecule of methane. H C [2] [Total: 10]

10 marks

Mark scheme: 2(a)(i) cracking ; 1 2(a)(ii) (from) brown / orange / yellow / red-brown ; (to) colourless / lighter ; 2 2(a)(iii) poly(ethene) ; 1 2(b)(i) hydrocarbon ; 1 2(b)(ii) covalent ; 1 2(b)(iii) carbon dioxide / CO2 ; water / H2O ; 2 Question Answer Marks 2(b)(iv) three further hydrogen atoms drawn around the carbon atom ; one pair of electrons between each hydrogen and the carbon ; 2

This question in 0653/32 Oct/Nov 2019

2 Petroleum is a mixture of compounds which are separated in a fractional distillation column. Process X changes molecules in one fraction, as shown in Fig. 2.1. fractional process X distillation column products strong heat petroleum Fig. 2.1 (a) The products of process X include alkenes. (i) Identify process X. … [1] (ii) Describe the colour change that is seen when aqueous bromine is mixed with an alkene. from … to … [2] (iii) Name the substance that is formed by the addition polymerisation of ethene. … [1] (b) Most of the compounds in petroleum are alkanes. Alkanes and alkenes contain carbon and hydrogen atoms only. (i) Name the type of compound that contains carbon and hydrogen atoms only. … [1] (ii) State the type of chemical bond that forms between carbon and hydrogen atoms. … [1] (iii) Identify the two products of the complete combustion of alkanes. … and … [2] (iv) The formula of methane is CH4. Complete the dot‑and‑cross diagram to show the shared electron pairs in a molecule of methane. H C [2] [Total: 10]

10 marks

Mark scheme: 2(a)(i) cracking ; 1 2(a)(ii) (from) brown / orange / yellow / red-brown ; (to) colourless / lighter ; 2 2(a)(iii) poly(ethene) ; 1 2(b)(i) hydrocarbon ; 1 2(b)(ii) covalent ; 1 2(b)(iii) carbon dioxide / CO2 ; water / H2O ; 2 Question Answer Marks 2(b)(iv) three further hydrogen atoms drawn around the carbon atom ; one pair of electrons between each hydrogen and the carbon ; 2

This question in 0653/33 Oct/Nov 2019

5 Refinery gas, gasoline and gas oil are fuels obtained from petroleum in the process shown in Fig. 5.1. refinery gas gasoline gas oil petroleum Fig. 5.1 (a) Suggest one use for bottled refinery gas fuel. … [1] (b) Petroleum is a mixture that contains alkanes. Alkanes are saturated compounds that contain carbon and hydrogen atoms only. The complete combustion of alkanes forms water and one other compound. (i) Name the type of compound that contains carbon and hydrogen atoms only. … [1] (ii) Identify one other compound that is formed during the complete combustion of alkanes. … [1] (iii) Describe one chemical test for water and give the positive result. test … result … [2] (c) Methane, CH4, is an alkane. The structure of a molecule of methane is shown in Fig. 5.2. H H C H H Fig. 5.2 (i) Name the type of bonding in methane. … [1] (ii) Explain how bonds form between carbon atoms and hydrogen atoms in methane. Use ideas about electrons. … … [1] (d) Ethene is an alkene. Alkenes are unsaturated compounds. (i) Describe the difference in the structure of molecules of alkenes and alkanes. Use ideas about bonds. … … [1] (ii) Name the addition polymer that forms from ethene monomer units. … [1] [Total: 9]

9 marks

Mark scheme: 5(a) heating / cooking ; 1 5(b)(i) hydrocarbon ; 1 5(b)(ii) carbon dioxide ; 1 5(b)(iii) reagent copper sulfate OR cobalt chloride ; result (white to) blue OR (blue to) pink ; result must match the reagent 2 5(c)(i) covalent ; 1 5(c)(ii) shared (pair) ; 1 5(d)(i) alkenes double (bonds) and alkanes (only) single (bonds) ; 1 5(d)(ii) poly(ethene) ; 1

This question in 0653/32 Feb/March 2020

8 (a) Sodium chloride is made when aqueous sodium hydroxide is mixed with dilute hydrochloric acid. State what happens to the pH of the mixture as the aqueous sodium hydroxide is added to the dilute hydrochloric acid. … [1] (b) Sodium is in Group I of the Periodic Table, and chlorine is in Group VII. (i) Describe the change in character of elements across a period in the Periodic Table from left to right. … … [1] (ii) Describe the trend in reactivity of Group I metals from lithium to potassium. … … [1] (iii) Describe the trend in physical state of Group VII elements from fluorine to iodine. … … [1] (c) Aqueous bromine reacts with alkenes. (i) State the colour change that occurs during this reaction. … [1] (ii) Name the reaction that produces alkenes from larger alkane molecules. … [1] [Total: 6]

6 marks

Mark scheme: 8(a) 1 8(b)(i) metal(lic) to non-metal(lic) ; 1 8(b)(ii) increases ; 1 8(b)(iii) gas to (liquid to) solid / increasing, melting / boiling point ; 1 8(c)(i) decolourises / brown disappears / brown to colourless ; 1 8(c)(ii) (catalytic) cracking ; 1

This question in 0653/31 Oct/Nov 2020

5 (a) Petroleum is a mixture of hydrocarbons. Useful products are obtained by process X and process Y, as shown in Fig. 5.1. process X process Y gasoline naphthanaphtha alkenes strong heat petroleum Fig. 5.1 (i) Process X separates gasoline and naphtha from petroleum. Name process X. … [1] (ii) Process Y produces alkenes. Name process Y. … [1] (iii) State whether process Y is a chemical change or a physical change. Explain your answer. change … explanation … … [1] (iv) Describe a chemical test for alkenes, and state the observation for a positive result. test … result … [2] (b) The structure of a molecule of propene, an alkene, is shown in Fig. 5.2. H H H H C C C H H Fig. 5.2 Water is formed during the complete combustion of propene. (i) Identify the other substance that is formed during this combustion. … [1] (ii) Name the gas in air that reacts with propene during combustion, and state the percentage of this gas in clean air. gas … percentage … [1] (iii) Use Fig. 5.2 to deduce the formula of propene. … [1] [Total: 8]

8 marks

Mark scheme: 5(a)(i) fractional distillation ; 1 5(a)(ii) cracking ; 1 5(a)(iii) change: chemical AND explanation: new substances are made / bonds are broken / new bonds are formed ; 1 5(a)(iv) test: (add aqueous) bromine ; result: (orange to) colourless / decolourises ; 2 5(b)(i) carbon dioxide / CO2 ; 1 5(b)(ii) gas: oxygen AND percentage: 21(%) ; 1 5(b)(iii) C3H6 ; 1

This question in 0653/31 May/June 2021

8 Methane, CH4, is a hydrocarbon. (a) State what is meant by hydrocarbon. … … [2] (b) Methane is an alkane. An alkane contains only single covalent bonds. Fig. 8.1 is a dot-and-cross diagram of a molecule of methane, CH4. Only the outer shell electrons are shown. H × H × C × H × H Fig. 8.1 Use Fig. 8.1 to describe what is meant by single covalent bonds. … … … [2] (c) The complete combustion of methane produces carbon dioxide and water. (i) Balance the equation for the complete combustion of methane. CH4 + … O2 CO2 + … H2O [2] (ii) State and explain whether the carbon in methane is oxidised or reduced in this reaction. carbon … explanation … … [1] (iii) Explain why argon, a noble gas, does not react with oxygen. Use ideas about electronic structure in your answer. … … [1] (d) Describe how the bonding in alkenes is different from the bonding in alkanes. … … [1] [Total: 9]

9 marks

Mark scheme: 8(a) (compound) containing carbon (atoms) and hydrogen (atoms) ; only ; 2 8(b) single: one pair of electrons / one dot and one cross ; covalent: electrons are shared / electrons inside two circles ; 2 8(c)(i) 2 ; 2 ; 2 8(c)(ii) oxidised AND gains oxygen ; 1 8(c)(iii) atoms of argon have full outer shells / 8 electrons in outer shells ; 1 8(d) alkenes contain a double bond / C=C (whereas alkanes contain only single bonds) ; 1

This question in 0653/31 Oct/Nov 2021

8 (a) Describe a chemical test for water and state the positive result. test … result … [2] (b) Compounds P and Q are two different types of hydrocarbon. • Compound P is a monomer in an addition polymerisation reaction. • Compound Q does not react with aqueous bromine. Identify these two types of hydrocarbon. compound P … compound Q … [2] (c) Methane is the main constituent of one fossil fuel. (i) State the name of this fossil fuel. … [1] (ii) Complete the dot-and-cross diagram in Fig. 8.1 to show all of the atoms and the bonding electrons in a molecule of methane. C H Fig. 8.1 [2] [Total: 7]

7 marks

Mark scheme: 8(a) test copper(II) sulfate ; 2 result turns (white to) blue ; OR test cobalt(II) chloride ; result turns (blue to) pink ; 8(b) compound P alkene / unsaturated ; 2 compound Q alkane / saturated ; 8(c)(i) natural gas ; 1 8(c)(ii) one pair of electrons correct ; 2 everything else correct ;

This question in 0653/31 Oct/Nov 2022

8 Methane, CH4, and ethene, C2H4, are hydrocarbons. (a) Methane is the main constituent of one fossil fuel. (i) State the name of this fossil fuel. … [1] (ii) State the type of chemical bonding in methane. … [1] (iii) Complete Fig. 8.1 to show the dot‑and‑cross diagram of a molecule of methane. Show only the outer shell electrons. H H C H H Fig. 8.1 [1] (iv) State the two products of the complete combustion of methane. 1 … 2 … [2] (b) Ethene is an unsaturated hydrocarbon. (i) State what is meant by the terms unsaturated and hydrocarbon. unsaturated … … hydrocarbon … … [2] (ii) State the process that produces ethene and other unsaturated hydrocarbon molecules from alkanes. … [1] (c) Hydrocarbon W turns aqueous bromine colourless. State whether hydrocarbon W is saturated or unsaturated. Give a reason for your answer. hydrocarbon W … reason … … [1] [Total: 9]

9 marks

Mark scheme: 8(a)(i) natural gas ; 1 8(a)(ii) covalent ; 1 8(a)(iii) four bonding pairs around the C atom ; 1 8(a)(iv) carbon dioxide / CO2 ; 2 water / H2O ; 8(b)(i) (unsaturated) contains a double bond ; 2 (hydrocarbon) contains carbon and hydrogen only ; 8(b)(ii) cracking ; 1 8(c) (hydrocarbon W) unsaturated AND 1 (reason) alkenes react with aqueous bromine / this shows a positive test for an alkene ;

This question in 0653/32 Feb/March 2023

5 (a) Ethane, C2H6, is an alkane. It is one of the saturated hydrocarbons present in refinery gas obtained from petroleum, as shown in Fig. 5.1. refinery gas petroleum Fig. 5.1 (i) State one use of refinery gas. … [1] (ii) Explain what is meant by hydrocarbon and saturated. hydrocarbon … … saturated … … [2] (b) Ethene, C2H4, is an unsaturated hydrocarbon. (i) State the process that produces unsaturated hydrocarbons from petroleum fractions. … [1] (ii) Describe the change in colour of aqueous bromine when it is added to ethene. from … to … [1] (iii) Complete the balanced equation for the complete combustion of ethene. C2H4 + …. O2 …. CO2 + …. H2O [2] (iv) State the name of the substance that is formed when many ethene monomer units join together. … [1] [Total: 8]

8 marks

Mark scheme: 5(a)(i) (bottled) gas for (domestic), heating / cooking ; 1 5(a)(ii) (hydrocarbon) molecule / compound, containing hydrogen / H and carbon / C only ; (saturated) only single bonds (between carbon atoms) / no double bonds ; 2 5(b)(i) cracking ; 1 5(b)(ii) (from) brown/orange/red-brown (to) colourless ; 1 5(b)(iii) (C2H4) + ..3.. O2  ..2.. CO2 + ..2.. H2O ;; LHS (1) RHS (1) 2 Question Answer Marks 5(b)(iv) poly(ethene) ; 1

This question in 0653/31 May/June 2023

8 (a) Methane, CH4, is the main constituent of natural gas. (i) Complete the word equation for the complete combustion of methane. methane + + water [1] (ii) Complete the dot‑and‑cross diagram in Fig. 8.1 to show the arrangement of electrons in a molecule of water. Show only the outer shell electrons. H O H Fig. 8.1 [2] (b) Ethene is an unsaturated hydrocarbon. Aqueous Y is an orange solution that is decolourised by ethene. It is used as a test for ethene. (i) State what is meant by unsaturated. … … [1] (ii) Identify Y. … [1] (iii) State the type of polymerisation that produces poly(ethene) from ethene. … [1] (c) At –120 °C methane is a gas and ethene is a liquid. Describe two differences between the particles in a gas and a liquid. 1 … … 2 … … [2] [Total: 8]

8 marks

Mark scheme: 8(a)(i) methane + oxygen  carbon dioxide + water ; 1 8(a)(ii) both correct bonding pairs ; molecule fully correct, i.e. four additional electrons on O and no extra electrons ; 2 8(b)(i) contains a double bond ; 1 8(b)(ii) (aqueous) bromine / Br2 ; 1 8(b)(iii) addition ; 1 8(c) any two from: separation: gas particles are, far apart / separated / not touching / spread out / liquid particles are, close together / touching / not spread out / not separated ; movement: gas particles, move fast(er) / move freely / move in all directions / move randomly / liquid particles, move (more) slowly / move over each other ; forces: gas particles have, no / weak forces of attraction between particles / liquids particles have stronger forces of attraction ; 2

This question in 0653/32 May/June 2023

5 Natural gas and petroleum are fossil fuels. (a) Methane is the main constituent of natural gas. Complete the word equation for the complete combustion of methane. methane + + [1] (b) Petroleum is a mixture of saturated hydrocarbon molecules. It is separated by the process shown in Fig. 5.1. fractions petroleum Fig. 5.1 (i) State the name of this process. … [1] (ii) State the name of the fraction used for bottled gas for heating and cooking. … [1] (c) Naphtha from petroleum is used to produce alkenes. (i) State the name of the process that is used to produce alkenes. … [1] (ii) Describe the colour change when aqueous bromine is added to an alkene. from … to … [1] (iii) Alkenes form addition polymers. Name one alkene and the addition polymer that it forms. alkene … addition polymer … [1] [Total: 6]

6 marks

Mark scheme: 5(a) 1 all correct ; 5(b)(i) fractional distillation ; 1 5(b)(ii) refinery gas ; 1 5(c)(i) cracking ; 1 5(c)(ii) orange / brown (to) colourless ; 1 5(c)(iii) any named alkene AND its addition polymer, e.g., ethene AND poly(ethene) ; 1

This question in 0653/32 Oct/Nov 2023

5 Natural gas and petroleum are fossil fuels. (a) Methane is the main constituent of natural gas. Complete the word equation for the complete combustion of methane. methane + + [1] (b) Petroleum is a mixture of saturated hydrocarbon molecules. It is separated by the process shown in Fig. 5.1. fractions petroleum Fig. 5.1 (i) State the name of this process. … [1] (ii) State the name of the fraction used for bottled gas for heating and cooking. … [1] (c) Naphtha from petroleum is used to produce alkenes. (i) State the name of the process that is used to produce alkenes. … [1] (ii) Describe the colour change when aqueous bromine is added to an alkene. from … to … [1] (iii) Alkenes form addition polymers. Name one alkene and the addition polymer that it forms. alkene … addition polymer … [1] [Total: 6]

6 marks

Mark scheme: 5(a) 1 all correct ; 5(b)(i) fractional distillation ; 1 5(b)(ii) refinery gas ; 1 5(c)(i) cracking ; 1 5(c)(ii) orange / brown (to) colourless ; 1 5(c)(iii) any named alkene AND its addition polymer, e.g., ethene AND poly(ethene) ; 1

This question in 0653/33 Oct/Nov 2023

8 (a) The fossil fuel petroleum is a liquid mixture of hydrocarbons. (i) Complete the sentence about hydrocarbons. Hydrocarbons are molecules that contain … and … only. [1] (ii) Describe the arrangement and motion of particles in a liquid. arrangement … … motion … … [2] (iii) Explain why the change in state from a liquid to a gas is described as a physical change. … … [1] (b) A diagram of the equipment used to separate petroleum is shown in Fig. 8.1. column petroleum Fig. 8.1 State the name of the separation process that uses this equipment. … [1] (c) Ethene is an unsaturated hydrocarbon. (i) Describe what is meant by unsaturated. … [1] (ii) Naphtha is obtained from petroleum. Naphtha undergoes a process to produce ethene. State the name of the process that produces ethene from naphtha. … [1] (iii) State the name of the type of chemical reaction that changes ethene into poly(ethene). … [1] [Total: 8]

8 marks

Mark scheme: 8(a)(i) carbon and hydrogen ; 1 8(a)(ii) (arrangement) close together / random ; (motion) move around each other ; 2 8(a)(iii) no new substance is made / can be reversed ; 1 8(b) fractional distillation ; 1 8(c)(i) contains a (C=C) double bond ; 1 8(c)(ii) cracking ; 1 8(c)(iii) addition polymerisation ; 1

This question in 0653/33 May/June 2024

8 (a) Complete the sentences about fuels. Use words from the list. Each word may be used once or not at all. bitumen fossil hydrocarbon methane petroleum Coal, … and natural gas are … fuels. The main constituent of natural gas is … . [3] (b) Petroleum is separated into useful fractions by fractional distillation. Draw one line from each fraction to its use. fraction use fuel in cars refinery gas road surfaces naphtha chemical feedstock bitumen heating and cooking [3] (c) The diagrams in Fig. 8.1 show the structures of compound F and compound G. H H H H H H H C C C H H C C C H H H H H compound F compound G Fig. 8.1 (i) State the name of the group of hydrocarbons to which compound F belongs. … [1] (ii) Compound G is an unsaturated hydrocarbon. Describe what is meant by unsaturated. … … [1] (iii) Describe one chemical test to distinguish between compounds F and G. State the observation for each compound. test … compound F … compound G … [3] [Total: 11]

11 marks

Mark scheme: 8(a) petroleum ; 3 fossil ; methane ; 8(b) 3 fraction use fuel in cars refinery gas road surfaces naphtha chemical feedstock bitumen heating and cooking correct line for refinery gas ; correct line for naphtha ; correct line for bitumen ; 8(c)(i) alkane(s) ; 1 8(c)(ii) contains a carbon–carbon double bond ; 1 8(c)(iii) test add aqueous bromine ; 3 compound F no change ; compound G decolorises / turns (from red-orange to) colourless ;

This question in 0653/31 Oct/Nov 2024

6 (a) The formulas of some compounds of carbon are shown. C2H4 CaCO3 CH4 CO CO2 Use the formulas of these compounds to answer the following questions. Each formula may be used once, more than once or not at all. State which compound: (i) decolourises aqueous bromine … [1] (ii) is the main constituent of natural gas … [1] (iii) forms poly(ethene) in an addition polymerisation reaction … [1] (iv) is a product of the complete combustion of alkanes and leads to global warming … [1] (v) is a toxic gas formed by incomplete combustion … [1] (vi) is a waste gas produced from digestion in animals … [1] (vii) is an acidic oxide. … [1] (b) State what is meant by a hydrocarbon. … … [1] (c) Bitumen and refinery gas are obtained from petroleum. Name one use of: bitumen … refinery gas. … [2] (d) Coal is a fossil fuel. During the combustion of coal, a compound that contains sulfur is made. Name this compound. … [1] [Total: 11]

11 marks

Mark scheme: 6(a)(i) C2H4 ; 1 6(a)(ii) CH4 ; 1 6(a)(iii) C2H4 ; 1 6(a)(iv) CO2 ; 1 6(a)(v) CO ; 1 6(a)(vi) CH4 ; 1 6(a)(vii) CO2 ; 1 6(b) (a compound that contains) carbon and hydrogen only ; 1 6(c) (bitumen) road surfaces ; 2 (refinery gas) heating / cooking ; 6(d) sulfur dioxide ; 1

This question in 0653/31 May/June 2025

5 (a) Fig. 5.1 shows an organic compound. H H H Cl H H C C C C C H H H H H H Fig. 5.1 (i) Deduce the molecular formula of the organic compound shown in Fig. 5.1. … [1] (ii) Explain why the organic compound shown in Fig. 5.1 is not a hydrocarbon. … … [1] (b) Fig. 5.2 is a diagram of the chemical structure of ethene. H H C C H H Fig. 5.2 (i) Name the group of hydrocarbons to which ethene belongs. … [1] (ii) Complete the symbol equation for the complete combustion of ethene in the presence of oxygen. C2H4 + … O2 … CO2 + … H2O [1] (iii) Complete the sentences about poly(ethene) using one word in each gap. Poly(ethene) is a polymer made from ethene. Polymers are large molecules built up from many smaller molecules called … . The formation of poly(ethene) is an example of … polymerisation. [2] [Total: 6]

6 marks

Mark scheme: 5(a)(i) C5H11Cl ; 1 5(a)(ii) any one from: 1 hydrocarbons contain carbon and hydrogen only ; (this compound) contains chlorine ; 5(b)(i) alkene ; 1 5(b)(iii) C2H4 + 3O2 → 2CO2 + 2H2O ; 1 5(b)(iii) monomers ; 2 addition ;

This question in 0653/32 Oct/Nov 2025

5 (a) Fig. 5.1 shows an organic compound. H H H Cl H H C C C C C H H H H H H Fig. 5.1 (i) Deduce the molecular formula of the organic compound shown in Fig. 5.1. … [1] (ii) Explain why the organic compound shown in Fig. 5.1 is not a hydrocarbon. … … [1] (b) Fig. 5.2 is a diagram of the chemical structure of ethene. H H C C H H Fig. 5.2 (i) Name the group of hydrocarbons to which ethene belongs. … [1] (ii) Complete the symbol equation for the complete combustion of ethene in the presence of oxygen. C2H4 + … O2 … CO2 + … H2O [1] (iii) Complete the sentences about poly(ethene) using one word in each gap. Poly(ethene) is a polymer made from ethene. Polymers are large molecules built up from many smaller molecules called … . The formation of poly(ethene) is an example of … polymerisation. [2] [Total: 6]

6 marks

Mark scheme: 5(a)(i) C5H11Cl ; 1 5(a)(ii) any one from: 1 hydrocarbons contain carbon and hydrogen only ; (this compound) contains chlorine ; 5(b)(i) alkene ; 1 5(b)(iii) C2H4 + 3O2 → 2CO2 + 2H2O ; 1 5(b)(iii) monomers ; 2 addition ;

This question in 0653/33 Oct/Nov 2025