formulae, equations and calculations

• Relative atomic mass

  The weighted mean mass of an atom of an element compared with one-twelfth of the mass of an atom of carbon-12.
• Relative isotopic mass

  The mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12.
• Relative molecular mass

  The weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12.
• relative formula mass

  The weighted mean mass of a formula unit compared with one-twelfth of the mass of an atom of carbon-12.
• empirical formula

  The simplest whole number ratio of atoms of each element present in a compound
• molecular formula

  shows the types and numbers of atoms combined in a single molecule of a molecular compound
• Percentage yield

  actual yield/theoretical yield x 100
• Atom economy

  (Molecular mass of desired products/ Molecular mass of all products) x 100