Question 1 of 25 Which statement describes the potential energy diagram of an exothermic
reaction?
A. The activation energy of the reactants is greater than the
activation energy of the products.
B. The potential energy of the products is equal to the potential
energy of the reactants.
C. The potential energy of the products is greater than the potential
energy of the reactants.
D. The potential energy of the reactants is greater than the potential
energy of the products.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.

it is reliable if two scientists recorded it