1. Title: Lesson 14 Preparing a Standard Solution and Back Titration Learning Objectives: – Prepare a standard solution to use in a titration practical.

2. Preparing a Standard Solution Prepare standard solutions of sodium carbonate. You will use these in a future lesson so make them well!

3. More Titration Problems… standard solution?

4. Solutions

5. Done in reverse by returning to the end point after it is passed. Used when end point is hard to identify or when one of the reactants is impure. A known excess of one reactant is added. The unreacted excess is then determined by titration against a standard solution. Subtract the unreacted amount from the original amount.

7. Questions…

8. 30.0g 80.7%

9. Questions…

10. Problem Time Write three stoichiometry problems using any of the ideas from the unit so far (make sure you know the answer). In ten minutes time you will need to give your problems to a classmate to solve.

11. Key Points

12. Remember! Alcohol is not the answer but it is a solution*! *Of ethanol, water and various other bits and pieces