Question

Of the following delta H°f is not zero for ______.

A. F2 (s)
B. O2 (g)
C. N2 (g)
D. C (graphite)
E. Cl2 (g)

Answer 1

The substances with a non-zero ΔH°f are O2 (g) and N2 (g).

Step-by-step explanation:

In this question, we have to identify which of the given substances have a standard enthalpy of formation (ΔH°f) that is not zero. The standard enthalpy of formation of any element in its standard state is zero by definition.

Based on this information, we can determine that the substances with a non-zero ΔH°f are:

B. O2 (g)

C. N2 (g)