Standard enthalpy change of combustion is defined as the enthalpy change when one mol of substance is completely burnt i

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Standard Enthalpy Change Of Combustion Is Defined As The Enthalpy Change When One Mol Of Substance Is Completely Burnt I 1 (44.19 KiB) Viewed 36 times

Standard enthalpy change of combustion is defined as the enthalpy change when one mol of substance is completely burnt in oxygen under standard conditions of 298 K and 1 atm. When fuel is combusted, a large quantity of energy is released and can be used to power anything from cars to household appliances. Ethene (CH) and ethyne (CH2) are two examples of important fuels. Given the following information: 2H2(g) + O2(g) → 2H20(1) C(s) + O2(g) → C02(9) C2H49) + 30,(9) ► 2002(g) + 2H20 (1) 2C2H2(g) +502(g) → 4C02(g) + 2H20(1) AH = -569 k) AH = -394 k) mol-1 AH = -1 428 kJ mol-1 AH = - = -2 600 k) (a) Calculate the standard enthalpy of formation of ethene using Hess' Law. (3 marks) (b) Calculate the standard enthalpy of formation of ethyne using Hess' Law. (4 marks) (c) Compare the efficiency of ethene and ethyne as fuel on the combustion of 1 kg of each of the compounds. (3 marks)