What is gram molecular volume ? Explain.

The gramme molecular volume is the volume occupied by one gramme mole of a substance in the gaseous or vapour state at STP.

The total gramme molecular volume of the substance is  22dm³or .22400cm³

At STP, the mass in gram of 22dm³ of a gas or vapour equals its gramme molecular weight.

The volume of one mole of a gas occupied at a standard temperature and pressure, STP, is defined as the gramme molecular volume