1. Titrations L.O: To understand how to set up a titration to find the concentration of an unknown acid / alkali.

2. The concentration of solutions is measured as the number of moles dissolved in one dm 3 of water (1dm 3 = 1000cm 3 = 1 litre). This concentration is given in mol dm 3 or is sometimes written M.e.g. if 2 moles of a substance are dissolved in 1 dm 3 of water, the solution is said to have a concentration of 2 mol/dm 3 Concentrations in solution Number of moles concentrationvolume

3. Moles in a solution. You are often given different concentrations of solutions in chemistry e.g. 0.5M HCl That means there are 0.5M in 1 litre (1000cm 3 ) So to work out the number of moles of a chemical in given volume of the solution No of moles = volume (l) X Moles per 1000cm 3 or mol/dm 3 Try this: how many moles are there in 100cm 3 (0.1L) of 2M HCl? 0.1 X 2 = 0.2 Moles

4. Copy and complete the table MolesConcentration (mol dm 3 ) Volume 0.13dm 3 0.5200cm 3 0.151dm 3 0.8600cm 3 0.012 0.20.5

5. Titrations http://www.youtube.com/watch?v=b8SOr- ABE8w&feature=related A solution becomes neutral with the right amount of acids and alkalis (end point)

6. Indicators Weak acid and strong alkali – phenolphthalein Strong acid and weak alkali – methyl orange FIND OUT WHAT COLOUR THE INDICATORS ARE IN ACIDS AND ALKALIS

7. In your titration measure the volume of acid needed to neutralise the alkali. Work out the number of moles in the acid and alkali you used. No of moles = volume (l) X Moles per 1000cm 3 or mol/dm 3 Are they the same?