C(graphite) + o2(g) → co2(g)δh o rxn = −393.5 kj/mol h2(g) + 1 2 o2(g) → h2o(l)δh o rxn = −285.8 kj/mol 2c2h6(g) + 7o2(g) → 4co2(g) + 6h2o(l)δh o rxn = −3119.6 kj/mol calculate the enthalpy change for the reaction below: 2 c(graphite) + 3h2(g) → c2h6(g)