1. Mole-Volume Relationship Molar Volume, STP, Molecular Spacing

2. Mole-Volume Relationship for a gas is constant due to the large amount of space between molecules. Contrast to a solid or liquid, where the molecules are much closer together and require varying amounts of space due to differences in sizes. Molar Volume is a unit of measurement used to express molar amounts of a gas. L/mol is the unit used to define molar volume. Contrast to: g/mol (the unit for solids and liquids).

3. The volume of a gas varies with temperature and pressure, therefore the volume of a gas is usually measured at STP (standard temperature and pressure). STP is defined as 0 o C and 1 atmosphere (atm) pressure. At STP, 1 mol (or 6.02 X 10 23 particles) is equal to 22.4 L.  For Example, 1 mole of Copper metal is 63.55 g/mol. 1 mole of N 2 gas at STP is 22.4 L/mol.