Question

Using the data below, calculate the enthalpy for the combustion of C to CO C(s) + O2(g)--> CO2 (g) ΔH1 = -393.5 kJ CO(g) + 1/2O2(g) -->CO2(g) ΔH2= -283.0kJ Target: C(s) + 1/2O2(g) --> CO(g) ΔH3=?? Group of answer choices

Answer 1

Answer:

ΔH = -110.5kJ

Explanation:

It is possible to obtain enthalpy of combustion of a particular reaction by the algebraic sum of similar reactions (Hess's law). Using:

1. C(s) + O₂(g) → CO₂(g) ΔH₁ = -393.5kJ

2. CO(g) + 1/2O₂(g) → CO₂(g) ΔH₂ = -283.0kJ

The sum of 1 -2 gives:

C(s) + O₂(g) + CO₂(g) → CO₂(g) + CO(g) + 1/2O₂(g)

C(s) + 1/2O₂(g) → CO(g) ΔH = -393.5kJ - (-283.0kJ) =

ΔH = -110.5kJ