What happens to the chemical potential of a pure gas at 1 bar?

The correct choice is that at 1 bar, the chemical potential of a pure gas equals the standard chemical potential, denoted as μ*. The chemical potential (μ) is a measure of the energy change associated with adding or removing a mole of substance from a system, and it varies with pressure and temperature.

At a defined pressure, such as 1 bar, the chemical potential of an ideal gas is referenced to its standard state, which is typically chosen at 1 bar and a specified temperature. Standard chemical potential (μ*) is a characteristic value for a substance at standard conditions, and it serves as a point of reference for understanding how the chemical potential behaves under varying conditions.

When a pure gas is at 1 bar, its chemical potential aligns with this standard value because the pressure condition corresponds with the reference state conditions used to define μ*. The relationship between chemical potential, their standard values, and system conditions is essential for evaluating thermodynamic processes in chemistry.