One mole of methane undergoes complete combustion in a stoichiometric amount of air. The reaction proceeds as CH4 + 2O2 → CO2 + 2H2O. Both the reactants and products are in gas phase. ΔH°298 = – 730 kJ/mole of methane. Mole fraction of water vapour in the product gases is about_____________________?

Question

Accepted Answer

0.19. The mole fraction of water is moles of H2O / total moles. Total moles = 1 (CO2) + 2 (H2O) = 3. Mole fraction = 2/3 ≈ 0.67. Wait, the question asks for the mole fraction of water vapour in the product gases based on the given answer A=0.19.