Of the following,ΔH°_f is not zero for ________. A)O₂ (g) B)C (graphite) C)N₂ (g) D)F₂ (s) E)Cl₂ (g)

Question

Quizplus · Accepted Answer

ΔH°_f is the enthalpy of formation at standard conditions, which means the formation of 1 mole of substance from its constituent elements in their standard states at 1 bar and 298 K. The enthalpy of formation of an element in its standard state is defined as zero. Therefore, ΔH°_f for C (graphite), N2 (g), O2 (g) and Cl2 (g) is zero. However, the enthalpy of formation of F2 (g) is not zero, and neither is the enthalpy of formation of solid elemental fluorine (F₂ (s)). Therefore, the correct answer is D.

Of the Following,ΔH°f Is Not Zero for ________

Of the Following,ΔH°_f Is Not Zero for ________