Amount of substance

• Sulphate ion

  SO4 2-
• What is meant by amount of substance?

  The amount of particles in a substance, measured in moles
• Avogadro's constant (N\/A)


  Particles per mole is equal to 6.02x10^23(mol-1)
• Avogadro's law

  Equal volumes of different gases at the same temperature and pressure will contain equal numbers of particles
• Molar mass


  Mass per mole of a substance (gmol-1)
• Molar gas volume

  Gas volume per mole (dm^3mol-1)
• Empirical formula


  The simplest ratio of elements in a compound
• Molecular formula


  The number and types of atoms of each element in a molecule
• How to calculate empirical formula

  S - Symbol

  M - Mass/g

  Ar - Atomic mass

  Di - Divide to find the moles

  Di - Divide again by the smallest value

  Ra - Ratio the values
• Anhydrous


  An ionic compound that contains no water molecules
• Hydrate


  An ionic compound that contains water molecules which are loosely attached within its structure
• Water of crystallisation


  Water molecules that surround a hydrated ionic compound
• How to calculate water of crystallisation

  step 1 ) write out both molecules

  step 2) Write masses for both

  step 3) find moles

  step 4) divide both by smallest
• Original concentration

  Total volume/ dilution factor
• Dilution equation


  Original concentration/ diluted concentration
• Ideal gas equation


  PV=nRT
• Standard temperature and pressure

  273K and 100kPa (1 atm)
• How to calculate percentage yield of a reaction
• Atom economy

  Molecular mass of desired products/ Sum of molecular mass of all reactants
• When is atom economy 100%?

  When one product is produced or when no greenhouses gases are produced