1 Introduction and definitions

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Oxford Textbook Pages : 124 - 128

CGP Revision Guide Pages : 68 - 69

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Show Specification Ref : 3.2.1a, 3.2.1b, 3.2.1c, 3.2.1d

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Question 1 / 5

June 2011 QP – Unit 1 AQA Chemistry A-level_question_2 do not write outside the box norgessaltpeter was the first nitrogen fertiliser to be manufactured in norway it has the formula ca no a norgessaltpeter can be made by the reaction of calcium carbonate with dilute nitric acid as shown by the following equation caco s hno aq ca no aq co g h o i in an experiment an excess of powdered calcium carbonate was added to cm of mol dm nitric acid a i calculate the amount in moles of hno in cm of mol dm nitric acid give your answer to significant figures mark a ii calculate the amount in moles of caco that reacted with the nitric acid give your answer to significant figures mark a iii calculate the minimum mass of powdered caco that should be added to react with all of the nitric acid give your answer to significant figures marks a iv state the type of reaction that occurs when calcium carbonate reacts with nitric acid mark wmp jun chem do not write outside the box b norgessaltpeter decomposes on heating as shown by the following equation ca no s cao s no g o g a sample of norgessaltpeter was decomposed completely the gases produced occupied a volume of m at a pressure of kpa and a temperature of c the gas constant r j k mol b i calculate the total amount in moles of gases produced marks b ii hence calculate the amount in moles of oxygen produced mark c hydrated calcium nitrate can be represented by the formula ca no xh o where x is an integer a g sample of ca no xh o contains g of water of crystallisation use this information to calculate a value for x show your working marks turn over wmp jun chem do not write outside the box fluorine and iodine are elements in group of the periodic table a explain why iodine has a higher melting point than fluorine marks extra space b i draw the shape of the nhf molecule and the shape of the bf molecule include any lone pairs of electrons that influence the shape in each case name the shape shape of nhf shape of bf name of shape of nhf name of shape of bf marks b ii suggest a value for the f n f bond angle in nhf mark c state the strongest type of intermolecular force in a sample of nhf mark wmp jun chem
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Question 2 / 5

January 2013 QP – Unit 2 AQA Chemistry A-level_question_1 section a answer all questions in the spaces provided do not write outside the box a figure shows the volume of hydrogen gas collected when a sample of magnesium reacted with an excess of dilute hydrochloric acid the rate of this reaction can be studied by measuring the time it takes for a given volume of hydrogen to be collected figure volume of hydrogen cm a i state the meaning of the term rate of reaction time s mark a ii state and explain what has happened to the rate of this reaction at point w in figure marks wmp jan chem do not write outside the box a iii in terms of collision theory explain why at a fixed temperature the rate of this reaction doubles when the concentration of the hydrochloric acid doubles marks b in a study of the reaction in part a a student referred to activation energy b i state the meaning of the term activation energy mark b ii complete figure by drawing the shape of the reaction profile from reactants to products for an exothermic reaction show the position of the products show and label the activation energy figure energy reactants question continues on the next page marks turn over wmp jan chem do not write outside the box c barium metal reacts very quickly with dilute hydrochloric acid but it reacts more slowly with water c i write an equation for the reaction of barium with water mark c ii a solution containing barium ions can be used to show the presence of sulfate ions in an aqueous solution of sodium sulfate write the simplest ionic equation for the reaction that occurs and state what is observed simplest ionic equation observation marks c iii state one use of barium sulfate in medicine explain why this use is possible given that solutions containing barium ions are poisonous use explanation marks wmp jan chem turn over for the next question do not write on this page answer in the spaces provided turn over wmp jan chem
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Question 3 / 5

June 2013 QP – Unit 2 AQA Chemistry A-level_question_10 section b answer all questions in the spaces provided do not write outside the box ethanol is an important industrial compound a ethanol can be produced by the hydration of ethene the equation for the equilibrium that is established is h c ch g h o g ch ch oh g h kj mol the operating conditions for the process are a temperature of c and a pressure of mpa under these conditions the conversion of ethene into ethanol is a i identify the catalyst used in this process deduce how an overall yield of is achieved in this process without changing the operating conditions marks a ii use your knowledge of equilibrium reactions to explain why a manufacturer might consider using an excess of steam in this process under the same operating conditions marks wmp jun chem do not write outside the box a iii at pressures higher than mpa some of the ethene reacts to form a solid with a relative molecular mass greater than deduce the identity of this solid give one other reason for not operating this process at pressures higher than mpa do not include safety reasons marks b write an equation for the reaction that has an enthalpy change that is the standard enthalpy of formation of ethanol marks c when ethanol is used as a fuel it undergoes combustion c i define the term standard enthalpy of combustion marks question continues on the next page turn over wmp jun chem c ii consider these bond enthalpy data do not write outside the box c h c c c o o o c o o h bond enthalpy kj mol use these data and the equation to calculate a value for the enthalpy of combustion of gaseous ethanol ch ch oh g o g co g h o g marks d gaseous ethanol can be used to convert hot copper ii oxide into copper d i deduce the role of ethanol in this reaction mark d ii draw the structure of the organic compound with mr that is produced in this reaction mark wmp jun chem
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Question 4 / 5

June 2015 QP – Unit 2 AQA Chemistry A-level_question_7 do not write outside the box a propanone can be formed when glucose comes into contact with bacteria in the absence of air a i balance the following equation for this reaction of glucose to form propanone carbon dioxide and water c h o ch coch co h o a ii deduce the role of the bacteria in this reaction mark mark b propanone is also formed by the oxidation of propan ol b i write an equation for this reaction using o to represent the oxidising agent mark b ii state the class of alcohols to which propan ol belongs mark wmp jun chem do not write outside the box c a student determined a value for the enthalpy change when a sample of propanone was burned the heat produced was used to warm some water in a copper calorimeter the student found that the temperature of g of water increased by c when mol of pure propanone was burned in air use the student s results to calculate a value in kj mol for the enthalpy change when one mole of propanone is burned the specific heat capacity of water is j k g marks question continues on the next page turn over wmp jun chem d define the term standard enthalpy of combustion do not write outside the box marks e use the mean bond enthalpy data in table and the equation given below table to calculate a value for the standard enthalpy change when gaseous propanone is burned marks table c h c c c o o h c o o o mean bond enthalpy kj mol ch coch g o g co g h o g wmp jun chem do not write outside the box f suggest two reasons why the value obtained by the student in question c is different from the value calculated in question e marks reason reason turn over for the next question turn over wmp jun chem
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Question 5 / 5

January 2011 QP – Unit 5 AQA Chemistry A-level_question_2 do not write outside the box the balance between enthalpy change and entropy change determines the feasibility of a reaction the table below contains enthalpy of formation and entropy data for some elements and compounds hf kj mol s j k mol n g o g no g c graphite c diamond a explain why the entropy value for the element nitrogen is much greater than the entropy value for the element carbon graphite marks b suggest the condition under which the element carbon diamond would have an entropy value of zero mark c write the equation that shows the relationship between g h and s for a reaction mark d state the requirement for a reaction to be feasible mark wmp jan chem do not write outside the box e consider the following reaction that can lead to the release of the pollutant no into the atmosphere n g o g no g use data from the table on page to calculate the minimum temperature above which this reaction is feasible marks f at temperatures below the value calculated in part e decomposition of no into its elements should be spontaneous however in car exhausts this decomposition reaction does not take place in the absence of a catalyst suggest why this spontaneous decomposition does not take place mark g a student had an idea to earn money by carrying out the following reaction c graphite c diamond use data from the table on page to calculate values for h and s for this reaction use these values to explain why this reaction is not feasible under standard pressure at any temperature h s explanation marks turn over wmp jan chem
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