Flexi Says: In solids, the molecules that make up the solid are packed very close together with very little space between them. By contrast, the molecules that make up gases are much farther apart, and will spread out to fill whatever space they are in. In standard temperature and pressure conditions, one mole of gas occupies 22.4 liters (L) of space--more space than eleven 2-liter bottles of soda! By contrast, one mole of a solid such as salt occupies much less one liter (about 0.03 L).
