PowerPoint Chemistry

1. Precipitation in Double Displacement Reactions PIERRE COMAS CRISTINA RÍOS

2. Introduction Double Displacement Reactions A double displacement reaction involves the reaction of two compounds to form two new compounds. In effect, the compounds change partners with each other.

3. Purpose Purpose The purposes of this experiment are: 1. To observeprecipitationreactionsbymixingaqueoussolutions of cations and anions. 2. To write and balancecompletechemicalequations for precipitationreactions

4. Materials The materials needed are the following: Pb(NO3)2 CaCl2 KI NaCl NaOH FeCl3 Na2CO3 CuSO4 AgNO3 Test tubes KNO3 Test tube racks

5. Procedure of these reactions Put 21 clean test tubes in a test tube rack. Add 6 drops of the solutions indicated which are: KI, NaCl, NaOH, FeCl3, KNO3, Na2CO3, CuSO4 to 7 clean test tubes . Add 6 drops of AgNO3 solution to each test tube. Observe and record information and colour of any precipitate formed . Do the same with Pb(NO3)2 and with CaCl2. Clean the test tubes and dispose of the waste in the waste container. And finally write correct equations for all of the reactions where a precipitate was formed.

6. Reactionswith AgNo3 When we add a small quantity of Potassium Iodide to Silver Nitrate two compounds are produced Potassium Nitrate and a precipitate of Silver Iodide. AgNO3 + KI -> KNO3 + AgI↓ The precipitate has a yellow colour.

7. AgNO3 and NaCl When we add a small quantity of Sodium Chloride solution to Silver Nitrate solution it produces Sodium Nitrate and a precipitate of Silver Chloride. AgNO3 + NaCl-> NaNO3 + AgCl↓ The precipitate has a white colour.

8. AgNO3 and CuSO4 Copper nitrate and Silver Sulphate are formed when Silver Nitrate and Copper Sulphate react with each other. The precipitate is Silver Sulphate. AgNO3 + CuSO4-> Cu(NO3)2 + Ag2SO4 The colour of the precipitate is a light blue.

9. AgNO3 and Na2CO3 Silver Nitrate and Sodium Carbonate react to form Sodium Nitrate and Silver Carbonate. The precipitate is Silver Carbonate. AgNO3 + Na2CO3 -> Na2CO3 + Ag2CO3↓ The precipitate’s colour is light green. .

10. AgNO3 and FeCl3 Iron Nitrate and Silver Chloride are produced when Silver Nitrate reacts with Iron(III) Chloride. AgNO3 + FeCl3-> Fe(NO39 + AgCl3↓ The precipitate´s colour is light yellow.

11. Reactions with Lead (II) Nitrate Potassium nitrate and Lead Iodide are formed when Lead (II) Nitrate reacts with Potassium Iodide . The precipitate is Lead Iodide. Pb(NO3)2 + 2KI -> 2KNO3 + PbI2 The precipitate´s colour is yellow.

12. Pb(NO3)2 and NaCl When Lead (II) Nitrate reacts with Sodium Chloride it produces Sodium Nitrate and Lead (II) chloride. Pb(NO3) + 2NaCl ->2NaNO3 + PbCl2 The precipitate has a white colour.

13. Pb(NO3)2 and KNO3 When Lead (II) Nitrate and Potassium Nitrate react with each other they produce equal products as reactants because, Potassium takes the place of Lead and Lead takes the place of Potassium. Pb(NO3)2 + KNO3 -> KNO3 + PbNO3 The precipitate is a transparent white.

14. Pb(NO3)2 and Na2CO3 When Lead (II) Nitrate and Sodium Carbonate react they produce Sodium Nitrate and Lead Carbonate as a precipitate. Pb(NO3)2 + Na2CO3 -> Na2NO3 + PbCO3 The precipitate has got a whitecolour.

15. Pb(NO3)2 and NaOH Sodium Nitrate and Lead (II) Hydroxide are formed when Lead (II) Nitrate and Sodium Hydroxide react with each other. Pb(NO3)2 + 2NaOH -> 2NaNO3 + Pb(OH)2 The precipitate has got a white colour.

16. In all the reactions Silver was a precipitate because Silver is a solid and does not mix in solutions and is left at the bottom of the test tube. The two cations which form precipitates are Iodine and Chloride. Conclusion

17. Remember: It is prohibited to drink any of the products used in this experiment.

18. Thanks for yourattention