If the amount of substance in moles can be determined, then each of these thermodynamic properties may be expressed on a molar basis, and their name may be qualified with the adjective molar, yielding terms such as molar volume, molar internal energy, molar enthalpy, and molar entropy. The symbol for molar quantities may be indicated by adding a subscript "m" to the corresponding extensive property. For example, molar enthalpy is H m . Molar Gibbs free energy is commonly referred to as chemical potential, symbolized by μ μ , particularly when discussing a partial molar Gibbs free energy μ μ i for a component i in a mixture.