Standard Molar Volume is the volume occupied by one mole of any gas at STP. Remember that "STP" is Standard Temperature and Pressure. Standard temperature is 0 &176:C or 273 K. Standard pressure is 1 atmosphere or 760 mm Hg (also called "torr").

1 mole of any gas at STP occupies 22.4 liters of volume. Using this information, the volume occupied by any number of moles (or grams) can be determined. Conversely, the number of moles present in any volume of gas at STP can also be determined, and if the identity of the gas is known, this number of moles can be converted to a mass.

Standard molar volume is also useful for Density determinations at STP.

If the molar mass can be determined, from the chemical formula, for instance, then the density can be calculated. If the density is known, then the molar mass can be determined.