Moles

• Particle Masses


  • Individual atoms are incredibly small
  • Their masses are insignificant and aren't practical to use in calculations
• Relative Molecular Mass


  The sum of the individual relative atomic masses
• Mole


  • Chemists' "counting unit"
  • Makes measuring amount and doing calculations much more convenient
  • The amount of a substance, represented by the symbol "n" and the unit mol
  • 1 mol of any element of molecule is 6.022x10^23 atoms of that element or molecule
• Mole


  • n(glucose) = 2 mol means "the amount of glucose molecules is 2 mols"
• Avogadro's number is 6.022x10^23
• Molar Mass


  • The mass, in grams, of 1 mol of an element or compound
  • Given the symbol, "M" and the unit, g mol^-1 or g/mol
  • C-12 is the reference for all these units with 1 mol of C-12 weighing exactly 12 grams
• Percentage Composition


  • Compounds are substances that contain two or more elements
  • The proportions of the different elements in a compound can be calculating by the looking at the ratio of atoms and relative atomic masses
  • These calculations are incredibly important when determining the economic viability of particular chemical processes (whether they will be profitable or not)