Which of the following is a statement of Hess's law? If a reaction is carried out in a series of steps, the ΔH for the reaction will equal the sum of the enthalpy changes for the individual steps. If a reaction is carried out in a series of steps, the ΔH for the reaction will equal the product of the enthalpy changes for the individual steps. The ΔH for a process in the forward direction is equal in magnitude and opposite in sign to the ΔH for the process in the reverse direction. The ΔH for a process in the forward direction is equal to the ΔH for the process in the reverse direction. The ΔH of a reaction depends on the physical states of the reactants and products.