In the context of chemistry, <answer>energy</answer> is an attribute of a substance as a consequence of its atomic, molecular or aggregate structure. Since a chemical transformation is accompanied by a change in one or more of these kinds of structure, it is invariably accompanied by an increase or decrease of <answer>energy</answer> of the substances involved. Some <answer>energy</answer> is transferred between the surroundings and the reactants of the reaction in the form of heat or light; thus the products of a reaction may have more or less <answer>energy</answer> than the reactants. A reaction is said to be exergonic if the final state is lower on the <answer>energy</answer> scale than the initial state; in the case of endergonic reactions the situation is the reverse. Chemical reactions are invariably not possible unless the reactants surmount an <answer>energy</answer> barrier known as the activation <answer>energy</answer>. The speed of a chemical reaction (at given temperature T) is related to the activation <answer>energy</answer> E, by the Boltzmann's population factor e−E/kT – that is the probability of molecule to have <answer>energy</answer> greater than or equal to E at the given temperature T. This exponential dependence of a reaction rate on temperature is known as the Arrhenius equation.The activation <answer>energy</answer> necessary for a chemical reaction can be in the form of thermal <answer>energy</answer>.
In the context of chemistry, what is an attribute of a substance as a consequence of it's atomic, molecular or aggregate structure?
energy