Edexcel Jan 2013 Paper 1 Q20

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20 This question is about the gas ethane, C2H6, and its reactions. (a) Write the equation, including state symbols, which represents the reaction taking place when the standard enthalpy change of combustion of ethane is measured. (b) Ethane can react with chlorine to form chloroethane and hydrogen chloride. C2H6(g) + Cl2(g) o C2H5Cl(g) + HCl(g) Bond CH CC CCl HCl ClCl Bond enthalpy/kJ mol1 413 347 346 432 243 Rewrite this equation using displayed formulae. Use the equation you have written, together with the bond enthalpy data, to calculate the enthalpy change for the reaction. (2) (4) *P41212A01924* 19 Turn over<br /> (c) This reaction takes place in a number of steps, some of which are shown below. Cl2 o(cid:1)(cid:1)(cid:1)(cid:19)(cid:36)(cid:77)(cid:116) Step 1 Step 2 CH3CH3(cid:1)(cid:12)(cid:1)(cid:36)(cid:77)(cid:116)(cid:1)(cid:1)(cid:1)o HCl + CH3CH2(cid:116) (i) State the type of reaction occurring in step 1 and the conditions needed for this step. (2) TypeConditions(ii) Complete the equation below for the third step of the reaction, and show the movement of electrons using the appropriate arrows. CH3CH2(cid:116)(cid:1)(cid:1)(cid:12)(cid:1)(cid:1)(cid:36)(cid:77)Cl o (iii) Write equations for two termination steps in this reaction. (d) Ethane can be cracked in industry. Write an equation for the cracking of ethane. (e) Suggest two reasons why cracking of larger alkane molecules is important in industry. (3) (2) (1) (2) Reason 1:Reason 2:(Total for Question 20 = 16 marks) TOTAL FOR SECTION B = 60 MARKS TOTAL FOR PAPER = 80 MARKS 20 *P41212A02024*<br />

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