Edexcel Jun 2016 (IAL) Paper 1 Q

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19 Cordless hair-stylers use 2-methylpropane as a fuel. The 2-methylpropane reacts with oxygen on the surface of a heated catalyst. (a) Draw the skeletal formula of 2-methylpropane. C4H10(g) + 6O2(g) (cid:111) 4CO2(g) + 5H2O(l) (b) When the hair-styler is switched on, the catalyst is heated using a battery. Suggest why the battery is not needed after the catalyst has been heated initially. (1) (2)(c) The standard enthalpy changes of formation for the three compounds are: Compound Standard enthalpy of formation / kJ mol1 C4H10(g) CO2(g) H2O(l) 134.5 393.5 285.8 (i) The standard enthalpy change of formation of H2O(g) is 241.8 kJ mol1. Explain why this is less negative than the standard enthalpy change of formation of H2O(l). (1)14 *P46662A01420* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br /> (ii) Use the data in the table to calculate the standard enthalpy change of combustion of 2-methylpropane in kJ mol1. Show your method, which may involve the use of a Hess cycle. Include a sign and units in your answer. (iii) A refill canister for the cordless hair-styler holds 15 g of 2-methylpropane. Calculate the energy in kJ which can be obtained from one canister. (3) (2) A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D A E R A S I H T N I E T I R W T O N O D *P46662A01520* 15 Turn over<br /> (d) The enthalpy change of the reaction can also be calculated using the cycle below. C4H10(g) + 6O2(g) (cid:111) 4CO2(g) + 5H2O(l) +8410 kJ mol1 +11280 kJ mol1 4C(g) + 10H(g) + 13 O(g) (i) Calculate the enthalpy change of the reaction using this cycle. (ii) The enthalpy change of vaporization of water was one piece of data used to calculate the enthalpy changes shown beside the arrows in the cycle. What other information was needed? (1) (1)(Total for Question 19 = 11 marks) 16 *P46662A01620* D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A D O N O T W R I T E I N T H I S A R E A<br />

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