What is the standard heat of reaction for the formation of no2(g) from no(g) and o2(g)? write the balanced equation first.

- 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.

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >