Question

what happens to the reaction 2NO2 <----> N2O4 + 57.2 kJ when the temperature of the reaction is increased?

Answer 1

1) Equilibrium reaction:

2NO2 <----> N2O4 + 57.2 kJ

2) The quantity 57.2 kJ on the right side indicates that the reaction generates heat, i.e. it is exothermic.

When you increase the temperature of an equilibrium chemical  reaction that is exothermic you displace the equilibrium to the left, meaningh that more ractant will be formed..

Answer: the equilibrium will be displaced to the left producing more reatant, NO2.