Difference in the potential energy of the reactants and products
Explanation:
The products have a lower potential energy than the reactants, and the sign of ΔH is negative. In an endothermic reaction, energy is absorbed. The products have a higher potential energy than the reactants, and the sign of ΔH is positive.
The pressure would increase. When the temperature change form cold to hot, the gas will find ways to escape from containment. Thus, if it cannot escape that pressure will keep on increasing as the temperature rises.
