quantitative chemistry

• Conservation of mass

  The total mass of the products equal the total mass of reactants
• Mass is conserved because no atoms are lost or made
• Chemical symbol equations must always be balanced
• Ionic equations can be used to simplify complicated equations
• In chemistry, the term ‘species’ refers to the different atoms, molecules or ions involved in a reaction
• The relative formula mass or a compound is the sum of relative atomic masses of all atoms shown in a formula
• Relative formula mass = (number of moles x relative molecular mass)
• Avogadro constant is 6.02 x 10^23
• A mol is a measure of the number of particles in a substance
• The msss of one mole of a substance is it’s relative atomic mass or relative formula mass in grams
• Amount (mol) = mass of substance (g) / formula mass (g)
• limiting reactant


  When one chemical is used up and stops the reaction going any further
• A chemical that is not fully used up is said to be in excess
• At room temperature and pressure, one mole of any gas take up a volume of 24dm3
• moles of a gas =

  Volume = amount (mol) x 24dm^3
• The concentration of a suction is measures using units of mol/dm3
• Acids and alkalis react together to form a neutral solution
• Titration is an accurate technique to find out how much of an acid is needed to neutralise and alkali
• An suitable indicator must be used in titration
• Concentration of a solution = amount of substance (mol) / volume (dm3)
• The percentage yield is the actual amount of product made compared to the theoretical maximum amount of product that could be made
• Percentage yield = (yield from reaction / maximum theoretical yield) x 10
• Atom economy

  measure of the amount of reactant that ends up in a useful product
• Production of ethanol

  • Hydration and fermentation