If you were to use the expression

= H - TS

to calculate the entropy change during reactions at 298K, 900K, and 2300K, you would find the values = -5.94, -6.04, and -6.06 cal deg, respectively, for the reactions involving two moles of NO.

Neither the heat of reaction nor the disorder produced by the reaction are very temperature sensitive, and most of the temperature dependence of the free energy (and therefore ) arises from the T term in the preceding equation.

The temperature magnifies the importance of the entropy change; a given amount of disorder produced in a reaction is more important in determining free energy and spontaneity at high temperatures than at low.