C3 - Quantitative Chemistry

• Law of conservation of mass = "Matter cannot be created or destroyed, just transformed."
• Relative Atomic Mass (Ar) is a way of comparing the masses of atoms of different elements. e.g. Ar of Carbon is 12.
• Relative Molecular Mass (Mr) is just all the relative atomic masses of the atoms in the compound added together. Relative Molecular Mass is measured in g/mol.
• Every piece of equipment have a level of uncertainty.

  
  

  E.g. If the beaker has an uncertainty of ± 0.5, if we measure 15.0ml, the uncertainty will be 14.5ml or 15.5ml.
• The range of a set of measurements is the difference between the largest and smallest value.
• % Uncertainty = range of measurements / mean x 100
• Uncertainty = range of measurements / mean
• Mole = a unit of amount of substance.
• Moles are Avogadro numbers.