1 Introduction

 

/
~
~
~
/

Show Learning Materials

3.4 Alkenes Page 1

Oxford Textbook Pages : 216 - 217, 219

CGP Revision Guide Pages : 143

/
/
/
/

Show Specification Ref : 3.3.4.1

/
/
/
/
Show past exam questions

Question 1 / 5

AQA Jan 2012 Paper 1 Q3 do not write outside the box hexane c h is a member of the homologous series of alkanes a i name the raw material from which hexane is obtained mark a ii name the process used to obtain hexane from this raw material mark b c h has structural isomers b i deduce the number of structural isomers with molecular formula c h write the number in this box space for working mark b ii state one type of structural isomerism shown by the isomers of c h mark c one molecule of an alkane x can be cracked to form one molecule of hexane and two molecules of propene c i deduce the molecular formula of x mark wmp jan chem do not write outside the box c ii state the type of cracking that produces a high percentage of alkenes state the conditions needed for this type of cracking type of cracking conditions marks c iii explain the main economic reason why alkanes are cracked mark d hexane can react with chlorine under certain conditions as shown in the following equation c h cl c h cl hcl d i both the products are hazardous the organic product would be labelled flammable suggest the most suitable hazard warning for the other product mark d ii calculate the percentage atom economy for the formation of c h cl mr in this reaction mark e a different chlorinated compound is shown below name this compound and state its empirical formula ch ch cl cl ch name empirical formula marks turn over wmp jan chem
Show answer

Question 2 / 5

AQA Jun 2010 Paper 1 Q6 do not write outside the box pent ene is a member of the alkene homologous series a pent ene can be separated from other alkenes state the physical property of alkenes that allows them to be separated from a mixture by fractional distillation mark b i state the meaning of the term structural isomerism marks b ii name the branched chain isomer of pent ene shown below ch ch cc mark b iii draw the structure of a functional group isomer of pent ene mark wmp jun chem do not write outside the box c the cracking of one molecule of compound x produces pent ene ethene and butane in a mol ratio deduce the molecular formula of x and state a use for the ethene formed molecular formula of x use of ethene marks turn over for the next question turn over wmp jun chem section b answer all questions in the spaces provided do not write outside the box iodine and graphite are both solids when iodine is heated gently a purple vapour is seen graphite will not melt until the temperature reaches k graphite conducts electricity but iodine is a very poor conductor of electricity a state the type of crystal structure for each of iodine and graphite marks b describe the structure of and bonding in graphite and explain why the melting point of graphite is very high marks extra space wmp jun chem
Show answer

Question 3 / 5

AQA Jun 2012 Paper 1 Q2 compound x is shown below it is a member of a homologous series of hydrocarbons do not write outside the box h h ccch c h a i deduce the general formula of the homologous series that contains x mark a ii name a process used to obtain a sample of x from a mixture containing other members of the same homologous series mark b there are several isomers of x b i give the iupac name of the position isomer of x mark b ii draw the structure of a functional group isomer of x c at high temperatures one molecule of c h can be converted into two molecules of x and one molecule of another compound c i write an equation for this reaction mark mark wmp jun chem do not write outside the box c ii state the name of the process used to obtain a high yield of x from c h give one reason why this process is used in industry name reason marks c iii state why high temperatures are needed for this process mark d compound x can be converted into compound y compound y is shown below hh ccch c h hhh d i suggest the formula of a reagent that could be added to x in order to convert it into y mark d ii give one use of y mark d iii write an equation to show the reaction of y in a limited supply of air to produce a solid and water only mark question continues on the next page turn over wmp jun chem do not write outside the box d iv when a sample of y contaminated with ch sh is burned completely in air a toxic gas is formed identify this toxic gas and suggest a compound that could be used to remove the toxic gas from the products of combustion toxic gas compound used to remove toxic gas marks d v suggest the name of the process that occurs when the toxic gas in part d iv is removed mark e explain why the boiling points of x and y are similar marks wmp jun chem do not write outside the box the following equation shows the reaction of a phosphine molecule ph with an h ion ph h ph a draw the shape of the ph molecule include any lone pairs of electrons that influence the shape mark b state the type of bond that is formed between the ph molecule and the h ion explain how this bond is formed name of bond how bond is formed marks c predict the bond angle in the ph ion mark d although phosphine molecules contain hydrogen atoms there is no hydrogen bonding between phosphine molecules suggest an explanation for this mark turn over wmp jun chem
Show answer

Question 4 / 5

AQA Jun 2013 Paper 2 Q9 do not write outside the box the alkene e but enenitrile is used to make acrylic plastics the structure of e but enenitrile is h c c c cn a i draw the structure of z but enenitrile mark a ii identify the feature of the double bond in the e and z isomers that causes them to be stereoisomers mark b draw the repeating unit of the polyalkene formed by addition polymerisation of e but enenitrile mark wmp jun chem c consider the infrared spectrum of e but enenitrile do not write outside the box transmittance wavenumber cm identify two features of the infrared spectrum that support the fact that this is the infrared spectrum for but enenitrile you may find it helpful to refer to table on the data sheet feature feature marks turn over for the next question turn over wmp jun chem
Show answer

Question 5 / 5

AQA Jun 2016 Paper 2 Q8 section b answer all questions in the spaces provided do not write outside the box two reactions of bromopentane ch ch ch chbrch are shown c h reaction ch ch ch chbrch reaction c h oh the c h formed in reaction exists as a mixture of three isomers one of which is pent ene two of the isomers are a pair of stereoisomers all three isomers decolourise bromine a the same reagent is used in both reactions the product is determined by the choice of conditions state the reagent and the conditions for each of reaction and reaction state the role of the reagent in each reaction name and outline the mechanism of reaction for the formation of pent ene marks wmp jun chem do not write outside the box b all three isomers of c h contain the same functional group draw the displayed formula of pent ene draw the structures of the pair of stereoisomers and give their full iupac names explain the origin of the stereoisomerism shown marks turn over wmp jun chem do not write outside the box c the rates of hydrolysis of two chloroalkanes can be investigated by adding aqueous silver nitrate to the chloroalkanes during the hydrolysis reactions chloride ions are liberated slowly precipitates of silver chloride are formed outline a method to compare the rate of hydrolysis of chlorobutane with that of chlorobutane state how the method would ensure a fair test marks wmp jun chem turn over for the next question do not write on this page answer in the spaces provided turn over wmp jun chem
Show answer
/
/
/
/
/
/