1. 2j Preparing and analysing

2. Last lesson - Precipitation reactions Reactions that produce an INSOLUBLE SALT

3. Testing for Cl -, Br - and I - ions Add SMALL amounts of silver nitrate solution to salts containing halogen ions that have been dissolved in dilute nitric acid. Type of ion (dissolved in HNO 3(aq) ) Result of adding dilute silver nitrate Cl - White precipitate of silver chloride Br - Cream precipitate of silver bromide I-I- Pale yellow precipitate of silver iodide

4. Testing for sulphate ions SO 4 2- (aq) Add SMALL amounts of barium chloride solution to salts containing sulphate ions that have been dissolved in dilute hydrochloric acid. If sulphate ions are present, a white precipitate of barium sulphate is formed.

5. Testing for sulphite ions SO 3 2- (aq) Add dilute hydrochloric acid. Test the gas given off for sulphur dioxide by passing through pink acidified potassium manganate solution which turns colourless.

6. Testing for carbonate ions CO 3 2- (aq) You know this one! Add dilute hydrochloric acid Test the gas given off for carbon dioxide (turns limewater “milky”)

7. Today’s lesson – Gas tests

8. You know all these already!

9. Gas tests? Ammonia Carbon dioxide Chlorine Hydrogen Oxygen Sulphur dioxide

10. Gas tests? Ammonia – Turns damp red litmus paper blue Carbon dioxide – turns limewater “milky” Chlorine – bleaches damp litmus paper (white) Hydrogen – lighted splint – “popping sound” Oxygen – relights a glowing splint Sulphur dioxide - pink acidified potassium manganate solution turns colourless

11. Solubility of different salts

12. Which dissolve? SaltSoluble? Sodium chloride Sodium bromide Sodium carbonate Sodium sulphate Potassium chloride Potassium bromide Etc. When you have finished can you write down some general rules for which slats are soluble/insoluble

13. Solubility of salts all common sodium, potassium and ammonium salts are soluble all nitrates are soluble common chlorides are soluble, except silver chloride common sulphates are soluble, except barium and calcium sulphates common carbonates and hydroxides are insoluble, except those of sodium, potassium and ammonium