Reactivity 2.1 How much? The amount of chemical change
Reactivity 2.1.1 and 2.1.2
Understandings:
  • Chemical equations show the ratio of reactants and products in a reaction (2.1.1).​
  • The mole ratio of an equation can be used to determine:
  •           the masses and/or volumes of reactants and products
              the concentrations of reactants and products for reactions occurring in solution (2.1.2).
Learning outcomes:
  • Deduce chemical equations when reactants and products are specified (2.1.1).
  • Calculate reacting masses and/or volumes and concentrations of reactants and products (2.1.2).
Additional notes:
  • Include the use of state symbols in chemical equations.​
  • Avogadro’s law and definitions of molar concentration are covered in Structure 1.4.
  • The values for Ar given in the data booklet to two decimal places should be used in calculations.
Linking questions:
  • Reactivity 3.2 When is it useful to use half- equations?​
  • Structure 1.5 How does the molar volume of a gas vary with changes in temperature and pressure?
This video covers how to balance chemical equations.
This video covers molar ratios. 
Reactivity 2.1.3
Understandings:
  • The limiting reactant determines the theoretical yield.
Learning outcomes:
  • Identify the limiting and excess reactants from given data.
Additional notes:
  • Distinguish between the theoretical yield and the experimental yield.​
This video covers how to determine the limiting reactant and excess reactant. 
Reactivity 2.1.4
Understandings:
  • The percentage yield is calculated from the ratio of experimental yield to theoretical yield.
Learning outcomes:
  • Solve problems involving reacting quantities, limiting and excess reactants, theoretical, experimental and percentage yields.
This video covers theoretical yield and percent yield.
Reactivity 2.1.5
Understandings:
  • The atom economy is a measure of efficiency in green chemistry.
Learning outcomes:
  • Calculate the atom economy from the stoichiometry of a reaction.
Additional notes:
  • Include discussion of the inverse relationship between atom economy and wastage in industrial processes.
  • The equation for calculation of the atom economy is given in the data booklet.
Linking questions:
  • Structure 2.4, Reactivity 2.2 The atom economy and the percentage yield both give important information about the “efficiency” of a chemical process. What other factors should be considered in this assessment?
This video covers to how calculate the atom economy for a reaction.