amount of substance

• Specific heat capacity, c

  The energy required to raise the temperature of 1 g of a substance by 1K.
• Stoichiometry

  The ratio of the amount, in moles, of each substance in a chemical reaction.
• Water of crystallisation

  Water molecules that are bonded into a crystalline structure of a compound.
• Relative atomic mass, Ar

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

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

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

  The weighted mean mass of a molecule of a compound compared with one-twelfth of the mass of an atom of carbon-12.
• Molar mass M

  The mass per mole of a substance, in units of g mol-1
• Amount of substance, n


  The quantity whose unit is the mole. Chemists use amount of substance as a means of counting atoms
• Atomic number Z

  The number of protons in the nucleus of an atom (also proton number)
• Avogadro's hypothesis

  Equal volumes of gases at the same temperature and pressure contain the same number of molecules
• One mole of carbon, C, atoms has a mass of 12 g
• One mole of hydrogen, H, atoms has a mass of 1 g
• One mole of magnesium, Mg atoms has a mass of 24.3 g
• One mole of iron, Fe, atoms has a mass of 55.8 g
• amount = n
• mass = m
• molar mass = M
• n = m/M OR moles = mass/Mr