Question

What is the enthalpy of combustion when 1 mol C6H6(g) completely reacts with oxygen?
2C6H6(g) + 15O2(g) mc001-1.jpg 12CO2(g) + 6H2O(g)

–6339 kJ/mol

–3169 kJ/mol

1268 kJ/mol

6339 KJ/mol

Answer 1

The given equation is for 2 mol C6H6 and (from the problem) the enthalpy change for that reaction is −6339 kJ. Per 1 mol C6H6:

ΔH = (−6339 kJ) / 2 = −3169.5 kJ ≈ −3169 kJ/mol.

Answer: −3169 kJ/mol.