Which of the following is a statement of Hess's law?
A)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.
B)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.
C)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.
D)The ΔH for a process in the forward direction is equal to the ΔH for the process in the reverse direction.
E)The ΔH of a reaction depends on the physical states of the reactants and products.

Question

Quizplus · Accepted Answer

Hess's law states that the enthalpy change for a reaction is independent of the route taken. Therefore, 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. This is represented mathematically as ΔHrxn = ΣΔHproducts - ΣΔHreactants. Choice B is incorrect because the enthalpy changes for the individual steps cannot be multiplied to obtain the overall enthalpy change. Choices C, D, and E are incorrect because they relate to different principles.

Which of the Following Is a Statement of Hess's Law