Question

Water gas (a mixture of carbon monoxide and hydrogen) is prepared by passing steam over red-hot coke: C(s) + H2O(g) → CO(g) + H2(g) For many years, water gas was used as a fuel in industry and for domestic cooking. Compare the heat produced by the complete combustion of 1 mole of methane (CH4) with a mole of water gas (0.50 mole H2 and 0.50 mole CO) under standard conditions. (Assume liquid water is formed.) What is the difference between the two values?

Answer 1

Answer:

-605,5 kJ/mol of energy

Explanation:

Combustion of CH₄, CO and H₂ are:

CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)   ΔH = -890 kJ/mol

CO(g) + ¹/₂O₂(g) → CO₂(g) ΔH = -283 kJ/mol

H₂(g) + ¹/₂O₂(g) → H₂O(l) ΔH = -286 kJ/mol

The heat combustion of methane gives -890 kJ/mol of energy. The water gas gives the average of energy between the reactions, that is:

-283kJ/mol -286kJ/mol /2 = -284,5 kJ/mol of energy

Difference between the two values is:

-890kJ/mol - (-284,5kJ/mol) = -605,5 kJ/mol of energy

I hope it helps!