1 Definition and formulae

Found it useful? Your friends might too!

 

/
~
~
~
/
Show Learning Materials


Oxford Textbook Pages : 172 - 173, 179 - 181

CGP Revision Guide Pages : 84 - 85

/
/
/
/

Show Specification Ref : 4.1.1b, 4.1.1c, 4.1.1d

/
/
/
/
Show past exam questions

Question 1 / 5

June 2010 QP – Unit 1 AQA Chemistry A-level_question_6 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 2 / 5

June 2012 QP – Unit 1 AQA Chemistry A-level_question_2 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 3 / 5

January 2011 QP – Unit 2 AQA Chemistry A-level_question_9 section b answer all questions in the spaces provided do not write outside the box a student devised an experiment to investigate the enthalpies of combustion of some alcohols the student chose the following series of primary alcohols name formula methanol ethanol propan ol butan ol pentan ol alcohol x heptan ol ch oh ch ch oh ch ch ch oh ch ch ch ch oh ch ch ch ch ch oh ch ch ch ch ch ch oh ch ch ch ch ch ch ch oh a i name alcohol x mark a ii state the general name of the type of series shown by these primary alcohols mark a iii draw the displayed formula of the position isomer of butan ol a iv using o to represent the oxidising agent write an equation for the oxidation of butan ol to form an aldehyde mark mark wmp jan chem a v draw the displayed formula of a functional group isomer of this aldehyde do not write outside the box b the student carried out a laboratory experiment to determine the enthalpy change when a sample of butan ol was burned the student found that the temperature of g of water increased by oc when x mol of pure butan ol was burned in air and the heat produced was used to warm the water mark use the student s results to calculate a value in kj mol for the enthalpy change when one mole of butan ol is burned the specific heat capacity of water is j k g marks extra space question continues on the next page turn over wmp jan chem c i give the meaning of the term standard enthalpy of combustion do not write outside the box marks extra space c ii use the standard enthalpy of formation data from the table and the equation for the combustion of butan ol to calculate a value for the standard enthalpy of combustion of butan ol ch ch ch ch oh i o g co g h o i h f kj mol ch ch ch ch oh i o g co g h o i marks extra space wmp jan chem do not write outside the box d the student repeated the experiment described in part b and obtained an experimental value for the enthalpy of combustion for each alcohol in this series these experimental values were then compared with calculated values from standard enthalpies of formation as shown in the graph below enthalpies of combustion values for a series of primary alcohols enthalpy of enthalpy of combustion combustion kj mol kj mol calculated experimental m of alcohol mr of alcohol d i in terms of bonds broken and bonds formed explain why the calculated values of enthalpies of combustion of these alcohols when plotted against mr follow a straight line marks extra space d ii give two reasons why the experimental values obtained by the student are lower than the calculated values using the enthalpy of formation data marks turn over wmp jan chem
Show answer

Question 4 / 5

June 2014 QP – Unit 2 AQA Chemistry A-level_question_7 do not write outside the box table gives the names and structures of some structural isomers with the molecular formula c h table name of isomer structure isomer pent ene ch ch chch ch isomer cyclopentane isomer methylbut ene ch chch ch isomer methylbut ene ch c chch isomer methylbut ene h c c ch ch ch a isomer exists as e and z stereoisomers a i state the meaning of the term stereoisomers marks a ii draw the structure of the e stereoisomer of isomer mark wmp jun chem do not write outside the box b a chemical test can be used to distinguish between separate samples of isomer and isomer identify a suitable reagent for the test state what you would observe with isomer and with isomer marks reagent observation with isomer observation with isomer c use table a on the data sheet when answering this question isomer and isomer have similar structures c i state the infrared absorption range that shows that isomer and isomer contain the same functional group mark c ii state one way that the infrared spectrum of isomer is different from the infrared spectrum of isomer mark question continues on the next page turn over wmp jun chem do not write outside the box d two alcohols are formed by the hydration of isomer draw the displayed formula for the alcohol formed that is oxidised readily by acidified potassium dichromate vi mark e isomer reacts with hydrogen bromide to give two structurally isomeric bromoalkanes e i name and outline a mechanism for the reaction of isomer with hydrogen bromide to give bromo methylbutane as the major product marks ch c chch hbr ch cbrch ch name of mechanism mechanism wmp jun chem do not write outside the box e ii the minor product in this reaction mixture is bromo methylbutane explain why this bromoalkane is formed as a minor product marks f name and outline a mechanism for the following reaction to form isomer state the role of the hydroxide ion in this reaction marks ch cbrch ch koh h c c ch ch ch kbr h o name of mechanism mechanism role of hydroxide ion turn over wmp jun chem
Show answer

Question 5 / 5

June 2016 QP – Unit 4 AQA Chemistry A-level_question_4 do not write outside the box compound x clch cocl is used as a reagent in organic synthesis a the mass spectrum of x contains several molecular ion peaks a i chlorine exists as the isotopes cl and cl in a ratio calculate the m z value of the most abundant molecular ion peak in the mass spectrum of x mark a ii the most abundant fragment ion in the mass spectrum of x has m z draw the displayed formula of this fragment ion mark a iii a molecular ion of x that contains one cl atom and one cl atom undergoes fragmentation to form an ion with m z and one other species write an equation for this fragmentation show which isotope of chlorine is present in each product species marks b one important reaction of x is in the preparation of compound p as shown alcl cl ch c cl ch cl hcl wmp jun chem b i draw the structure of the electrophile formed by the reaction of x with alcl do not write outside the box mark b ii outline the mechanism for the reaction of the electrophile from part b i with benzene in the preparation of p marks c compound q is an alternative product that could be formed when x reacts with benzene cl ch describe how you could distinguish between p and q by a test tube reaction give the reagent used and the observation with each compound marks reagent observation with p observation with q turn over wmp jun chem do not write outside the box d x is also used to make the compound hoch cooh this compound is polymerised to form the polymer known as pga pga is used in surgical sutures stitches d i draw the repeating unit of pga mark d ii production of pga occurs via a cyclic compound two hoch cooh molecules react together to form the cyclic compound and two molecules of water draw the structure of this cyclic compound mark e poly propene is also used in surgical sutures e i draw the repeating unit of poly propene mark wmp jun chem do not write outside the box e ii suggest an advantage of surgical sutures made from pga rather than from poly propene explain your answer marks turn over for the next question turn over wmp jun chem
Show answer
/
/
/
/
/
/