Answer:
- 113.10 kJ/mol.
Explanation:
Firstly, we should write the balanced equation of NO₂ formation.
2NO + O₂ → 2NO₂.
We have the standard heat of formation (ΔH°f) of:
ΔH°f for NO = 90.4 kJ/mol.
ΔH°f for O₂ = 0.0 kJ/mol. (element)
ΔH°f for NO₂ = 33.85 kJ/mol.
∵ ΔH° for the reaction = ∑(ΔH°f)products - ∑(ΔH°f)reactants = [2(33.85 kJ/mol)] - [1(0.0 kJ/mol) + 2(90.4 kJ/mol)] = 67.7 kJ/mol - 180.8 kJ/mol = - 113.10 kJ/mol.
