Title: Lesson 14 Preparing a Standard Solution and Back Titration

Learning Objectives:

– Prepare a standard solution to use in a titration practical.

Preparing a Standard Solution

• Prepare standard solutions of sodium carbonate.

• You will use these in a future lesson so make them well!

More Titration Problems…

standard solution?

Solutions

• 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.

Questions…

Questions…

30.0g

80.7%

Questions…

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.

Key Points

volume

molesionconcentrat

Remember!

Alcohol is not the answer but it is a solution*!

*Of ethanol, water and various other bits and pieces