Consider the following statements:
(1) Rate of a process is directly proportional to its free energy change
(2) The order of an elementary reaction step can be determined by examining the stoichiometry
(3) The first-order reaction describes an exponential time course.
Of the statements:

2 and 3 are correct

Let's evaluate each statement to determine its validity:

(1) Rate of a process is directly proportional to its free energy change:

This statement is incorrect. The rate of a process is not directly proportional to its free energy change. The rate of a chemical reaction is determined by factors such as the activation energy, temperature, and concentration of reactants, but not directly related to the free energy change.

(2) The order of an elementary reaction step can be determined by examining the stoichiometry:

This statement is correct. The order of an elementary reaction step can indeed be determined by examining the stoichiometry. The stoichiometry of the reactants in an elementary step corresponds to the order of that particular step in the overall reaction mechanism.

(3) The first-order reaction describes an exponential time course:

This statement is correct. A first-order reaction follows an exponential time course. The rate of a first-order reaction is directly proportional to the concentration of the reactant, and as the reaction proceeds, the concentration of the reactant decreases exponentially over time.

Based on the evaluation of each statement, the correct option is (3) 2 and 3 are correct.