(c) Alkenes such as butene and ethene are more reactive than alkanes.Alkenes are used in the petrochemical industry to make a range of products, whichincludes polymers and alcohols.(i) Dibromoethane is used as a pesticide. Complete the equation for its preparationfrom ethene.C C + B 2 →HHHH[1](ii) The structural formula of a poly(alkene) is given below.nCCH 3CCH 3H HDeduce the structural formula of its monomer.[2](iii) How is butanol made from butene, CH 3 – CH 2 – CH = CH 2 ? Include an equation inyour answer................................................................................................................................................................................................................................................................... [2](iv) Cracking changes alkanes into alkenes. How could an alkene be converted into analkane? Include an equation in your answer................................................................................................................................................................................................................................................................... [2]PhysicsAndMathsTutor.com
Question
(c) Alkenes such as butene and ethene are more reactive than alkanes.Alkenes are used in the petrochemical industry to make a range of products, whichincludes polymers and alcohols.(i) Dibromoethane is used as a pesticide. Complete the equation for its preparationfrom ethene.C C + B 2 →HHHH1 The structural formula of a poly(alkene) is given below.nCCH 3CCH 3H HDeduce the structural formula of its monomer.2 How is butanol made from butene, CH 3 – CH 2 – CH = CH 2 ? Include an equation inyour answer................................................................................................................................................................................................................................................................... 2 Cracking changes alkanes into alkenes. How could an alkene be converted into analkane? Include an equation in your answer................................................................................................................................................................................................................................................................... [2]PhysicsAndMathsTutor.com
Solution
(i) The reaction of ethene with bromine to form dibromoethane is as follows:
C2H4 + Br2 → C2H4Br2
(ii) The monomer of the given poly(alkene) is:
CH2=CH-CH3
(iii) Butanol is made from butene through the process of hydroboration-oxidation. The reaction is as follows:
CH3-CH2-CH=CH2 + H2O → CH3-CH2-CH2-CH2OH
(iv) An alkene can be converted into an alkane through the process of hydrogenation. The reaction is as follows:
R-CH=CH-R + H2 → R-CH2-CH2-R
In these reactions, R represents any alkyl group.
Similar Questions
Which of the following are monomers used in addition polymerisation?AlcoholsCarboxylic acidsAlkanesAlkenes2What is the name of the process used to obtain monomer alkenes from the products of fractional distillation? CombustionPolymerisationEsterificationCracking3Which of the following statements about the addition polymerisation of ethene is not correct?Poly(ethene) is the polymerEthene is the monomerThe C=C bond in each monomer is replaced by a C-C bondThe monomers are joined together by ionic bonds4Polymers have many uses in everyday life. Which of the following is not a use of polymers?ElectronicsCosmetic productsFood flavouringFood storage 5Which of the following is a disadvantage of many polymers?They are very strongThey are not biodegradableThey are easy to shapeThey have very high melting points
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Alkanes and alkenes are both series of hydrocarbons.(a) (i) Explain the term hydrocarbon................................................................................................................................................................................................................................................................... [1](ii) What is the difference between these two series of hydrocarbons?..............................................................................................................................................................................................................................................
b) Ethene, CH2 =CH 2 , and propene, CH 2 =CHCH 3 , can both be converted into polymers.(i) What type of polymerisation takes place when ethene forms a polymer?....................................................................................................................................... [1](ii) What is the empirical formula of the polymer formed from ethene?....................................................................................................................................... [1](iii) Propene has the structural formula CH2 =CHCH 3 .Draw two repeat units of the polymer made from propene.[2](c) Ethene will react with steam to form ethanol.Propene will react with steam to form two isomers, both of which are alcohols.Suggest the structures of these alcohols.PhysicsAndMathsTutor.com
State the general formula for alkanes and alkynes. (2 Marks)Alkanes: ______________________________________________________________________________________________________________________________________________________________Alkynes: ______________________________________________________________________________________________________________________________________________________________
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