Final answer:
The molar specific density of water vapor refers to the density of water vapor per mole of water molecules. It can be calculated using the ideal gas law by relating the density to the partial pressure and temperature of the vapor.
Step-by-step explanation:
The molar specific density for water vapor refers to the density of water vapor per mole of water molecules. It is calculated by dividing the mass of the water vapor by the molar volume, which is the volume occupied by one mole of gas. In the case of water vapor, the molar specific density can be calculated using the ideal gas law by relating the density to the partial pressure and temperature of the vapor. For example, at a temperature of 20.0°C, a vapor density of 17.2 g/m³ creates a partial pressure equal to the vapor pressure of water at that temperature.