11.5. Alkenes
A subsection of Chemistry, 0620, through 11. Organic chemistry
Listing 10 of 149 questions
The table shows the structures of four hydrocarbons. P Q R S CH3–CH3 CH2=CH2 CH2=CH–CH3 CH2=CH–CH2–CH3 Why are compounds P, Q, R and S known as hydrocarbons? CompoundP is saturated. What is meant by the term saturated ? CompoundP undergoes a substitution reaction with chlorine. What is meant by the term substitution reaction? State a condition required for this reaction to occur. Write a chemical equation for this reaction. CompoundR undergoes an addition reaction with bromine. Why is this reaction an addition reaction? A compound containing bromine is formed in this reaction. Draw the structure of this compound. Show all of the atoms and all of the bonds.  To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Draw the structure of an unbranched isomer of compoundS. Show all of the atoms and all of the bonds. Name this unbranched isomer of compoundS. structure name  CompoundQ undergoes polymerisation. Name the polymer formed. Complete the chemical equation to show the polymerisation of compoundQ. n CH2=CH2  Amino acids undergo polymerisation to form proteins. Part of a protein molecule with the linkages missing is shown. Draw the linkages on the diagram. Show all of the atoms and all of the bonds. N H C O  The structure shows an ester. CH2 C O O CH2 CH3 CH2 CH3 Write the word equation for a reaction which could be used to make this ester. 
0620_s18_qp_41
THEORY
2018
Paper 4, Variant 1
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This question is about bromine and compounds of bromine. Use the kinetic particle model to describe the arrangement and type of motion of the molecules in: ● liquid bromine ● bromine gas.  The graph shows how the volume of bromine gas changes with temperature. The pressure is kept constant. volume of bromine gas temperature Describe how the volume of the bromine gas changes with temperature. Complete the word equation to show the halogen and halide compound which react to form the products bromine and potassium chloride. + bromine + potassium chloride  Explain, in terms of the reactivity of the halogens, why aqueous bromine will not react with aqueous potassium chloride. Bromine reacts with hydrogen sulfide, H2S. Complete the chemical equation for this reaction. + H2S HBr + S  The energy level diagram for this reaction is shown. energy progress of reaction reactants products Explain how this diagram shows that the reaction is exothermic. Describe a test for bromide ions. test observations  
0620_s19_qp_32
THEORY
2019
Paper 3, Variant 2
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The structures of five alkenes, A, B, C, D and E, are shown. C C A H H H H C C B CH3 H H H C C C CH2CH3 H H H C C D CH2CH2CH3 H H H C C E CH2CH2CH2CH3 H H H What is the general formula of alkenes? What is the molecular formula of alkeneD? Predict which alkene, A, B, C, D or E, has the highest boiling point. Explain your answer. alkene explanation  Which alkene, A, B, C, D or E, diffuses most quickly? Explain your answer. alkene explanation  A student added aqueous bromine to alkeneC. C C C CH2CH3 H H H Describe the colour change seen and draw the structure of the product. Show all of the atoms and all of the bonds. colour change from to structure  Two different alcohols can be produced from alkeneB by an addition reaction. C C B CH3 H H H Draw the structures of the two alcohols. Show all of the atoms and all of the bonds.  State the reagent and conditions needed to produce an alcohol from alkeneB. reagent conditions  AlkeneC can be converted into a polymer. C C C CH2CH3 H H H What type of polymerisation occurs? Suggest the name of the polymer formed. Complete the chemical equation to show this polymerisation. C C CH2CH3 H H H n  State the empirical formula of the polymer formed. 
0620_s19_qp_41
THEORY
2019
Paper 4, Variant 1
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The properties of five alkenes at room temperature are shown in the table. alkene number of carbon atoms in a molecule state at room temperature density in g / cm3 boiling point / °C ethene gas 0.0012 –104 propene gas 0.0018 –47 butene gas 0.0024 pentene liquid 0.64 hexene liquid 0.67 Answer these questions using only the information in the table. Predict the boiling point of butene.  °C Describe the general trend in the density of the alkenes. Suggest why the densities of the first three alkenes are much lower than the density of pentene and hexene. Complete the chemical equation for the complete combustion of propene. 2C3H6 + O2 → 6CO2 + 6H2O Describe a test for carbondioxide. test observations  Universal indicator is added to an aqueous solution of carbondioxide. ● ● What colour change is observed? from green to ● ● Give a reason for your answer.  When propene undergoes incomplete combustion, carbonmonoxide is formed. What condition is needed for incomplete combustion? Give one adverse effect of carbonmonoxide on health. 
0620_s20_qp_31
THEORY
2020
Paper 3, Variant 1
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The structure of myrcene is shown. C C H H H H H C C H H H H H C C C C C H H C H H H H Deduce the formula of myrcene to show the number of atoms of carbon and hydrogen. Myrcene is found in some plants. The coloured compounds in plant leaves can be separated by chromatography. Complete the diagram by putting the correct labels in the boxes. beaker lid  Myrcene is an unsaturated hydrocarbon. Describe a chemical test to distinguish between a saturated and an unsaturated hydrocarbon. test observations with saturated hydrocarbon observations with unsaturated hydrocarbon  Butane is a saturated hydrocarbon. To which homologous series does butane belong? Draw a circle around the correct answer. alcohol alkane alkene carboxylic acid Large hydrocarbons can be cracked to form smaller hydrocarbons. Complete the chemical equation for cracking tridecane, C13H28, to form an alkene and one other hydrocarbon. C13H28 → C3H6 +  Ethene is an alkene. Draw the structure of ethene showing all of the atoms and all of the bonds.  Complete the sentences about the separation of hydrocarbons from petroleum using words from the list. bitumen combustion condense crystallisation distillation evaporate gasoline kerosene melt Hydrocarbons are separated in a fractionating column by fractional . Hydrocarbons with lower boiling points move further up the column. When the temperature in the column falls below the boiling points of the hydrocarbons they . The fraction at the bottom of the column which is used for making roads is called .  
0620_s20_qp_31
THEORY
2020
Paper 3, Variant 1
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The structure of two organic compounds, F and G, are shown. C C C C C C C C H H H H H H H H F H H H H H H H H H H H H H H H H C C C C C C C C G CompoundF is an unsaturated compound. Describe a chemical test for an unsaturated compound. test observations  CompoundF is reduced to compoundG using hydrogen and a catalyst. State what is meant by the term catalyst. CompoundG is a saturated hydrocarbon. Name the saturated hydrocarbon which contains two carbon atoms. CompoundG is oxidised by nitricacid to compoundH. The structure of compoundH is shown. C H H C H H C H H C H H H C H H C C C H H O O H O O H Deduce the formula of compoundH to show the number of carbon, hydrogen and oxygen atoms. CompoundH contains two carboxylic acid functional groups. Ethanoicacid also contains a carboxylic acid functional group. Draw the structure of ethanoicacid. Show all of the atoms and all of the bonds.  Describe the observations made when ethanoicacid reacts with: universal indicator solution sodium.  A student’s graph of how the pH changes when aqueous ammonia is added slowly to dilute ethanoicacid is shown. volume of aqueous ammonia added / cm3 pH Deduce the pH of the dilute ethanoicacid before the addition of aqueous ammonia.  pH = Deduce the volume of aqueous ammonia added when the pH is neutral.  cm3 CompoundH reacts with compoundJ to form a polymer. CompoundJ has the formula HOCH2CH2OH. State the name of the –OH functional group in compoundJ. Ethene polymerises to form poly. Choose one word from the list that best describes the type of reaction that occurs. Draw a circle around the correct answer. addition combustion cracking reduction 
0620_s21_qp_33
THEORY
2021
Paper 3, Variant 3
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Questions Discovered
149