5 Kinetics

 

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Oxford Textbook Pages : 96 - 103

CGP Revision Guide Pages : 42 - 45

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Show Specification Ref : 3.1.5.1, 3.1.5.2, 3.1.5.3, 3.1.5.4, 3.1.5.5

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Question 1 / 5

AQA Jun 2011 Paper 1 Q6 section b answer all questions in the spaces provided do not write outside the box a there is a risk of gas explosions in coal mines this risk is mainly due to the presence of methane if the percentage of coal mine methane cmm in the air in the mine is greater than the explosion risk is much lower cmm slowly escapes from the mine into the atmosphere write an equation to show the complete combustion of methane suggest one reason why there is a much lower risk of an explosion if the percentage of cmm is greater than state why it is beneficial to the environment to collect the cmm rather than allowing it to escape into the atmosphere marks extra space wmp jun chem do not write outside the box b methane can be obtained from crude oil some of this crude oil contains an impurity called methanethiol ch sh this impurity causes environmental problems when burned write an equation to show the complete combustion of methanethiol state why calcium oxide can be used to remove the sulfur containing product of this combustion reaction state one pollution problem that is caused by the release of this sulfur containing product into the atmosphere marks extra space turn over for the next question turn over wmp jun chem do not write outside the box pentane is a member of the alkane homologous series a give the general formula for the homologous series of alkanes mark b one of the structural isomers of pentane is dimethylpropane draw the displayed formula of dimethylpropane state the type of structural isomerism shown marks wmp jun chem
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Question 2 / 5

AQA Jun 2013 Paper 1 Q2 do not write outside the box a the hydrocarbon but ene c h is a member of the homologous series of alkenes but ene has structural isomers a i state the meaning of the term structural isomers marks a ii give the iupac name of the position isomer of but ene mark a iii give the iupac name of the chain isomer of but ene mark a iv draw the displayed formula of a functional group isomer of but ene mark wmp jun chem do not write outside the box b but ene burns in a limited supply of air to produce a solid and water only b i write an equation for this reaction mark b ii state one hazard associated with the solid product in part b i mark c one mole of compound y is cracked to produce two moles of ethene one mole of but ene and one mole of octane c h only c i deduce the molecular formula of y mark c ii other than cracking give one common use of y mark d in cars fitted with catalytic converters unburned octane reacts with nitrogen monoxide to form carbon dioxide water and nitrogen only d i write an equation for this reaction mark d ii identify a catalyst used in a catalytic converter mark turn over wmp jun chem do not write outside the box in a new material called graphane was discovered the diagram shows part of a model of the structure of graphane each carbon atom is bonded to three other carbon atoms and to one hydrogen atom a deduce the type of crystal structure shown by graphane mark b state how two carbon atoms form a carbon carbon bond in graphane mark c suggest why graphane does not conduct electricity mark d deduce the empirical formula of graphane mark wmp jun chem
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Question 3 / 5

AQA Jan 2011 Paper 2 Q2 do not write outside the box the diagram below shows a maxwell boltzmann distribution for a sample of gas at a fixed temperature ea is the activation energy for the decomposition of this gas number of molecules with a given energy ea energy a i on this diagram sketch the distribution for the same sample of gas at a higher temperature marks a ii with reference to the maxwell boltzmann distribution explain why an increase in temperature increases the rate of a chemical reaction marks extra space wmp jan chem do not write outside the box b dinitrogen oxide n o is used as a rocket fuel the data in the table below show how the activation energy for the decomposition of dinitrogen oxide differs with different catalysts n o g n g o g without a catalyst with a gold catalyst with an iron catalyst with a platinum catalyst ea kj mol b i use the data in the table to deduce which is the most effective catalyst for this decomposition mark b ii explain how a catalyst increases the rate of a reaction marks extra space turn over wmp jan chem
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Question 4 / 5

AQA Jun 2012 Paper 2 Q6 do not write outside the box chloromethanes such as dichloromethane and trichloromethane are produced in industry as they have many uses trichloromethane has been used in the manufacture of the refrigerant chlorodifluoromethane a chlorine can react with dichloromethane ch cl to form trichloromethane chcl a i write an equation for each of the following steps in the mechanism for this reaction initiation step first propagation step second propagation step marks a ii give one essential condition for this reaction and name the type of mechanism essential condition type of mechanism marks question continues on the next page turn over wmp jun chem do not write outside the box b an organic product x with mr is obtained when chlorine reacts with trichloromethane b i write an equation for the overall reaction of chlorine with trichloromethane to form x by the same mechanism as that outlined in part a i mark b ii the following infrared spectrum was obtained for a sample of x produced in this reaction transmittance wavenumber cm use this infrared spectrum to explain why it is possible to deduce that this sample of x contains no trichloromethane you may find it helpful to refer to table on the data sheet marks extra space wmp jun chem do not write outside the box c explain with the aid of equations and the intermediates that form in the ozone layer why the european union has banned the use of chlorodifluoromethane chclf as a refrigerant marks extra space d the compound tetrafluoropropene is the refrigerant used in all new car air conditioners d i draw the displayed formula for tetrafluoropropene d ii give one reason why tetrafluoropropene is a more environmentally acceptable refrigerant than chlorodifluoromethane mark mark turn over wmp jun chem
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Question 5 / 5

AQA Jun 2014 Paper 2 Q8 section b answer all questions in the spaces provided do not write outside the box the carboxylic acid methylbutanoic acid is used to make esters for perfumes the following scheme shows some of the reactions in the manufacture of this carboxylic acid ch chch oh ch chch br reaction reaction ch chch cooh ch chch cn methylbutanoic acid reaction a one of the steps in the mechanism for reaction involves the replacement of the functional group by bromine a i use your knowledge of organic reaction mechanisms to complete the mechanism for this step by drawing two curly arrows on the following equation marks br h c ch ch o h h c ch ch br h o ch ch wmp jun chem do not write outside the box a ii deduce the name of the mechanism in question a i give the iupac name of ch chch br marks b reaction is an acid catalysed reaction in which water is used to break chemical bonds when the cn functional group is converted into the cooh functional group infrared spectroscopy can be used to distinguish between the compounds in this reaction deduce the name of the type of reaction that occurs in reaction identify one bond in ch chch cn and a different bond in ch chch cooh that can be used with infrared spectroscopy to distinguish between each compound for each of these bonds give the range of wavenumbers at which the bond absorbs use table a on the data sheet when answering this question marks question continues on the next page turn over wmp jun chem do not write outside the box c when methylbutanoic acid reacts with ethanol in the presence of an acid catalyst an equilibrium is established the organic product is a pleasant smelling ester ch chch cooh ch ch oh ch chch cooch ch h o an ester the carboxylic acid is very expensive and ethanol is inexpensive in the manufacture of this ester the mole ratio of carboxylic acid to ethanol used is to rather than to c i use le chatelier s principle to explain why a to mole ratio is used in your explanation you should not refer to cost marks extra space c ii explain how a catalyst increases the rate of a reaction marks extra space wmp jun chem
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