APFIVE Standard Enthalpy of Formation Comparison
How does the standard enthalpy of formation of a compound differ from that of an element in its standard state?
A
The standard enthalpy of formation of a compound is always positive, while that of an element in its standard state is always negative.
B
The standard enthalpy of formation of a compound is non-zero, while that of an element in its standard state is zero.
C
The standard enthalpy of formation of a compound is expressed in kJ/mol, while that of an element in its standard state is expressed in cal/g.
D
The standard enthalpy of formation of a compound is measured at 0°C, while that of an element in its standard state is measured at 25°C.