Question

Calculate the enthalpy of formation if 78.5 g of carbon dioxide in the following reaction:

C(s) + H2O(g) --> CO2(g)

Use the following equations:

a) H2O(l) --> H2(g) + (1/2)O2(g): Δ°f = +285.8 kJ/mol

b) C2H6(g) --> 2C(s) + 3H2(g): Δ°f = +84.7 kJ/mol

c) 2CO2(g) + 3O2(g) --> C2H6(g) + (7/2)O2(g): Δ°f = +1560.7kJ/mol

Answer 1

I don't believe you can do that.
C(s) + H2O(g) ==> CO2(g)
a. The equation is not balanced.
b. In those equations to be used you don't have H2O(g) anywhere but only H2O(l)
c. The equation you have posted isn't balanced. You're OK with C but O doesn't balance and there's no H on the left. Try again.