The state function which is not zero at the standard state is:

At the standard state (298 K, 1 bar, 1 M concentration), enthalpy (ΔH), internal energy (ΔU), and Gibbs free energy (ΔG) of elements in their standard form are taken as zero by convention. However, entropy (S) is an absolute quantity and is not zero at the standard state. It is determined based on the third law of thermodynamics, which states that only a perfectly crystalline substance at 0 K has zero entropy.