Question

Use Hess’s Law to calculate the enthalpy change for the reaction.

C2H4(g) + H2(g) → C2H6(g) ∆Hrxn = ?

Given:

C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) ∆Hrxn 1 = -1410.9kJ

2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l) ∆Hrxn 2 = -3119.4kJ

2H2(g) + O2(g) → 2H2O(l) ∆Hrxn 3 = -571.6kJ

Answer 1

∆Hrxn 1 + ∆Hrxn 3 - ∆Hrxn 2 = ?

-1410.9kJ - 571.6kJ + 3119.4kJ = ?

-2801.1kJ