On completion of the unit you should be able to:

1. balance chemical equations.
2. interpret balanced equations in terms of moles, mass units and number of particles.
3. given the number of moles (or mass or number of particles) of one substance calculate the number of moles ( or mass or number of particles) of another substance in the balanced equation.
4. define limiting and excess reactants.
5. identify the following types of reactions:

  • synthesis
  • decomposition
  • combustion
  • single-replacement
  • double-replacement
  • neutralization

6. define endothermic and exothermic reactions.
7. define acids and bases.

6.1 Law of conservation of energy
6.2 Chemical reactions: Law of conservation of mass
Reading: Hebden – page 105-106
6.3 Balancing chemical equations
Reading: Hebden – page 107-112
6.4 What is an aqueous solution?

Dissolving NaCl (1st video)
NaCl (s) Na+ (aq) + Cl (aq)

Dissolving NaCl (2nd video)
NaCl (s) Na+ (aq) + Cl (aq)

Dissolving copper(II) chloride
CuCl2 (s) Cu+2 (aq) + 2 Cl (aq)
6.5 Types of Reactions
Five major classes of chemical reactions

  1. Combination or Synthesis reactions
  2. Decomposition Reactions
  3. Single-replacement reactions
  4. Double-replacement reactions
  5. Combustion reactions

Demonstrations of the five major classes of chemical reactions

    • Synthesis or Combination
      Cu (s) + S (g) CuS (s)
    • Decomposition
      Ca(OH)2 (s) CaO (s) + H2O (g)
    • Single Replacement
      2 Al (s) + Fe2O3 (s) 2 Fe(s) + Al2O3 (s)
    • Double Replacement
      KI (aq) + Hg2(NO3)2 (aq) KNO3 (aq) + HgI (s)
    • Combustion
      CH4 (g) + 2 O2 (g) CO2 (g) + 2 H2O (l)
Reading: Hebden – page 114-118
6.6 Endothermic and exothermic reactions
Bill Nye The Science Guy on Chemical Reactions
6.7 Acids and bases

Balance chemical equations
Classify and balance chemical equations
Predict and balance chemical equations