1. Do Now: Complete the empirical formula worksheet. Ask someone that was in P5 Science yesterday for help if you don’t understand.

2. Flame Tests And Precipitation Reactions. To be able to describe: Flame tests to identify metal ions. Lithium, Sodium, Potassium, Calcium, Barium. Precipitation reactions: The precipitates formed when different ions react with Sodium Hydroxide.

3. http://www.youtube.com/watch?v=rEWLFH-QpWE Method: – dip a clean flame test loop in the sample solution – hold the flame test loop at the edge of a Bunsen burner flame – observe the changed colour of the flame, and decide which metal it indicates – clean the loop in acid and rinse with water, then repeat steps 1 to 3 with a new sample Describe flame tests to identify metal ions. Flame Tests:

4. metalflame test colour bariumpale green calciumyellow-red coppergreen-blue lithiumred sodiumorange potassiumlilac Describe flame tests to identify metal ions. Flame Tests

5. Sometimes when two solutions are mixed, they react to form an insoluble solid product. For example, mixing solutions of lead nitrate and sodium chloride produces a yellow precipitate of lead chloride. The insoluble solid product is called a precipitate. You can spot a precipitate because the mixture goes cloudy. lead nitrate Pb(NO 3 ) 2 (aq) sodium chloride 2NaCl (aq) lead chloride PbCl 2 (s) sodium nitrate 2NaNO 3 (aq)   + + + + Precipitation Reactions

6. Metal IonReacts WithColour of PPTE Al 2+ NaOHWhite Ca 2+ NaOHWhite Mg 2+ NaOHWhite Cu 2+ NaOHBlue Fe 2+ NaOHGreen Fe 3+ NaOHBrown If you get a white precipitate: Add more sodium hydroxide solution, aluminium precipitate will dissolve. If the white precipitate does not dissolve then the metal ion is calcium or magnesium. These can be distinguished using a flame test (magnesium ions have no flame colour).flame test What colour would we get for a flame test for Calcium ions?

7. aluminium chloride + sodium hydroxide aluminium hydroxide + sodiumchloride AlCl 3(aq) + 3NaOH (aq) Al(OH) 3(s) + 3NaCl (aq) The ionic equation is Al 3+ (aq) + 3OH - (aq) Al(OH) 3(s) Aluminium hydroxide is white.white calcium chloride + sodium hydroxide calcium hydroxide + sodium chloride. CaCl 2(aq) + 2NaOH (aq) Ca(OH) 2(s) + 2NaCl (aq) The ionic equation is Ca 2+ (aq) + 2OH - (aq) Ca(OH) 2(s) Calcium hydroxide is white.white

8. magnesium chloride + sodium hydroxide magnesium hydroxide + sodium chloride MgCl 2(aq) + 2NaOH (aq) Mg(OH) 2(s) + 2NaCl (aq) The ionic equation is Mg 2+ (aq) + 2OH - (aq) Mg(OH) 2(s) Magnesium hydroxide is white.white copper(II) chloride + sodium hydroxide copper(II) hydroxide + sodium chloride CuCl 2(aq) + 2NaOH (aq) Cu(OH) 2(s) + 2NaCl (aq) The ionic equation is Cu 2+ (aq) + 2OH - (aq) Cu(OH) 2(s) Copper(II) hydroxide is blue.blue

9. iron(II) chloride + sodium hydroxide iron(II) hydroxide + sodium chloride. FeCl 2(aq) + 2NaOH (aq) Fe(OH) 2(s) + 2NaCl (aq) The ionic equation is Fe 2+ (aq) + 2OH - (aq) Fe(OH) 2(s) Iron(II) hydroxide is green.green iron(III) chloride + sodium hydroxide iron(III) hydroxide + sodium chloride FeCl 3(aq) + 3NaOH (aq) Fe(OH) 3(s) + 3NaCl (aq) The ionic equation is Fe 3+ (aq) + 3OH - (aq) Fe(OH) 3(s) Iron(III) hydroxide is brown.brown

10. Applications: Precipitation reactions have a number of other uses: production of coloured pigments for paints and dyes removal of toxic chemicals from water separation of reaction products. Most precipitation reactions are very fast reactions that occur between ions. This makes them very useful for identifying specific ions based on the type of precipitate formed. A lead iodide precipitate.

11. Reactions of Carbonates All metal carbonates react with dilute hydrochloric acid to produce Carbon Dioxide. – Write the reactions of Calcium Carbonate, Sodium Carbonate and Magnesium carbonate with Hydrochloric acid: – Remember to write word then balanced symbol equations – check, the group numbers to help you to balance the equations. Carbon dioxide precipitates Limewater: – Can you remember the reaction for this (C1 Limestone cycle).