| A | B |
|---|
| Atomic mass | Weighted average mass of a naturally occurring mixture of an element's isotopes. |
| amu | Atomic mass unit; equal to one twelfth of the mass of a carbon-12 atom. |
| Mole | The amount of a substance that contains 6.02 x 10^23 atoms or molecules . |
| Avogadro's number | The number of atoms in 12 g of carbon-12; equals 6.02 x 10^23. |
| Molar mass | The mass in grams of one mole of a substance. |
| Molecular mass | The sum of the atomic masses of the atoms in that molecule. |
| Formula unit | A group containing the kinds and numbers of atoms or ions in the chemical formula for that substance. |
| Formula mass | The sum of the atomic masses of the atoms in the formula unit. |
| Empirical formula | A chemical formula that includes positive integers giving the simplest ratio of the atoms or each element in a compound. |
| Molecular formula | A chemical formula that describes the actual numbers of atoms of the elements in one molecule of a compound. |
