Question

question 18 of 25
what best describes the enthalpy of formation of a substance?
a. the total thermal energy of all the molecules in the substance
b. the energy needed to cause the substance to change phases
c. the energy change that happens when a substance forms from its elements
d. the energy absorbed or released in a chemical reaction

Explanation:

The enthalpy of formation is defined as the energy change when a substance is formed from its constituent elements in their standard states. Option A refers to internal energy, option B is related to latent - heat for phase change, and option D is the enthalpy change of a general chemical reaction.

Answer:

C. The energy change that happens when a substance forms from its elements