Question

Find ΔH for C3H8(g)+6H2O(g)→3CO2(g)+10H2 given C3H8 (g) + 3 H2O (g) → 3 CO (g) + 7 H2 (g) ΔH = 499 kJ CO (g) + H2O (g) → CO2 (g) + H2 (g) ΔH = -41 kJ

Answer 1

C3H8(g)+6H2O(g)→3CO2(g)+10H2

C3H8 (g) + 3 H2O (g) → 3 CO (g) + 7 H2 (g) ΔH = 499 kJ

CO (g) + H2O (g) → CO2 (g) + H2 (g) ΔH = -41 kJ

Lets number the reaction as 0, 1, 2 from top to bottom

required reaction should be written in terms of other reaction

This is Hess Law

required reaction can be written as:

reaction 0 = +1 * (reaction 1) +3 * (reaction 2)

So, ΔHo rxn for required reaction will be:

ΔHo rxn = +1 * ΔHo rxn(reaction 1) +3 * ΔHo rxn(reaction 2)

= +1 * (499) +3 * (-41)

= 376 KJ

Answer: 376 KJ