Lab 6 Instructor Notes

Lab 6: Types of Reactions

Remind Students:

  • Goggles MUST be worn whenever ANY group has chemical at their station.
  • Review safety
    • HCl and NaOH are caustic. Use caution.
  • Make sure they secure all equipment in bin when moving between the cart and their stations.
  • All glassware must be cleaned and dry (in their bin) before leaving lab.

When reviewing the protocol explain:

  • Signs of a chemical reaction and how to detect each:
    • Temperature change (put finger on the underside of the well plate).
    • Color change (spontanteous ie not blue + yellow = green)
    • Gas evolution (Bubbles but will not be as obvious today as before)
    • Precipitation (solution will become cloudy).
    • pH changes (Use litmus or pH paper today)
  • Writing formulas (remind them to make the table to find the correct formula).
  • Balancing equations (change coefficient only, not subscripts).
  • Types of Reactions (Main Types).
    • Synthesis
    • Decomposition
    • Combustion – we will not see this today.
    • Single Replacement
    • Double Replacement
  • Aqueous reaction types
    • Gas Evolving
    • Acid-Base
    • Precipitation
      • Solubility rules –they should have seen this but may review briefly.
    • Redox
      • Oxidation numbers –they should have seen this but may review briefly.

Net Ionic equations – applicable for acid-base AND precipitation reactions. They may need an example of this.

Remind them that for EACH reaction today, they will be responsible for:

  • Observing the reaction (signs of a chemical reaction if they occurred)
  • Identifying the main type of reaction.
  • Identifying the types of aqueous reaction (may be more than 1).

For several reactions they will also be:

  • Predicting products (with the correct formula)
  • Balancing the chemical equation.