Given the following reactions and subsequent ∆h values what is the ∆h for the reaction below?
4co2(g) + 2h2o(g) 2c2h2(g) + 5o2(g)
given:
c2h2+> c2h6 ∆h = -94.5kj
h2o > h2 + 1/2 o2 ∆h = 71.2kj
c2h6 + 7/2 o2 > 2co2 + 3h2o ∆h = -283kj

The heat of a reaction can be calculated from the heat of formation of each substance in the reaction. It is calculated as the sum of the heat of formation of each substance.

C2H2+2H2> C2H6                               ∆H = (-94.5kJ)
2(H2O > H2 +1/2O2)                            ∆H = 2(71.2kJ)
C2H6 + 7/2 O2 > 2CO2 + 3H2O       ∆H = (-283kJ)

C2H2 + 5/2O2 = 2CO2 + H2O                 ∆H = -235.1 kJ

4CO2 + 2H2O  = 2C2H2 + 5O2              ∆H = 470.2 kJ

Idid the calculation and i get 875,000,000 which can be written as 8.75 x 10^6?