Hess's Law Problem #6

Question

What is the enthalpy for the reaction: C2H4 + H2 --> C2H6 given the following equations:

C2H4(g) + 3O2(g) --> 2CO2(g) + 2H2O(l) = -1401kJ/mole

C2H6(g) + 7/2O2(g) --> 2CO2(g) + H2O(l) =-1550kJ/mole

H2(g) + 1/2O2(g) --> H2O(l) =-286kJ/mole

Answer 1

C2H4(g) + 3O2(g) --> 2CO2(g) + 2H2O(l) .. -1401kJ/mole

2CO2(g) + H2O (l) --> C2H6(g) + 7/2 O2(g) .. +1550 kJ/mole

H2(g) + 1/2 O2(g) --> H2O(l) .. -286 kJ/mole

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C2H4(g) + 3 O2(g) + 2CO2(g) + H2O(l) + H2(g) + 1/2 O2(g) --> 2CO2(g) + C2H6(g) + 7/2 O2(g) + H2O(l)

C2H4(gO + H2(g) --> C2H6(g) .. -140 +1550 -286 = 1124 kJ/mole