During a thermochemical calculation a student attempted to find the enthalpy change for
C(s, graphite) + O₂(g) → CO₂(g)
using the two equations
(1) C(s, graphite) + 21 O₂(g) → CO(g) ΔH = −110.5 kJ
(2) CO(g) + 21 O₂(g) → CO₂(g) ΔH = −283.0 kJ.
The student mistakenly reversed equation (2) but kept its ΔH unchanged and therefore reported an overall ΔH of +172.5 kJ.
Calculate the correct ΔH (in kJ) for the formation of CO₂(g) from C(s) and O₂(g).