| A | B |
| percent composition | a description of the relative amounts of each element in a compound |
| empirical formula | the lowest whole- number ratio of the atoms of the elements in a compound |
| 22.4 L | the volume occupied by one mole of any gas at STP |
| molar mass | the mass (in grams) of one mole of a compound |
| mole | the SI unit representing 6.02 X 10^23 representative particles of a substance |
| Avogadro's number | 6.02 X 10^23 particles |
| standard temperature and pressure (00 C, 1 atm) | the temperature and pressure at which one mole of gas occupies a volume of 22.4 L |
| molar volume | volume of a gas that contains one mole of the gas, is 22.4 L at STP |
| Avogadro’s hypothesis | equal volumes of gases at the same temperature and pressure contain equal numbers of particles |
| convert number of atoms to moles | divide number of atoms by 6.02 X 10^23 |