To have a standard enthalpy of formation referenced to 0 J/mol, the substance must: I) be a simple substance (chemical element)
II) be in its most stable form
III) be under 1 atm of pressure
IV) have a concentration of 1.0000 M

Question

Quizplus · Accepted Answer

To have a standard enthalpy of formation referenced to 0 J/mol, the substance must be a simple substance (chemical element) in its most stable form, and under 1 atm of pressure. The concentration of the substance does not affect its standard enthalpy of formation, so option IV is not necessary. Therefore, the best choice is I and II for a simple substance in its most stable form, and III for 1 atm of pressure. Thus, option B is the correct answer.

To Have a Standard Enthalpy of Formation Referenced to 0