The reaction is exothermic and
You know that the balanced chemical equation for your reaction looks like this
and that when 2 moles of nitric oxide,
This means that when the reaction takes place, energy is actually being released.
In other words, the energy needed to break the bonds of the reactants is exceeded by the energy released when the product is formed,
Simply put, the reaction gives off more than it takes in.
This is characteristic of an exothermic process, so your reaction will be exothermic.
As a rule of thumb, the amount of heat lost or gained by a system is represented from that system's point of view.
When heat is being given off, as is the case here, the system is losing heat to the surroundings. In other words, it ends up will less energy than it started with. If that is the case, then the sign of