The document summarizes several chemistry experiments involving redox reactions: 1) An experiment where iron(III) chloride reacts with zinc, producing a green solution containing iron(II) ions. Zinc undergoes oxidation and iron(III) undergoes reduction in this redox reaction. 2) An experiment verifying that iodide ions act as a reducing agent by reducing acidified potassium manganate(VII) in a galvanistic cell containing a U-tube filled with sulfuric acid and electrodes. 3) Suggestions that sodium, potassium or lithium could be the metal M that reacts with oxygen to form an alkaline solution, along with the half reactions for this oxidation and

1. Part 1 seminar camp science= chemistry

2. Seminar part 1) SPM 2009 9 (a) Diagram 9 shows the apparatus and observations for a redox reaction between iron(III) chloride solution and a metal. At the beginning of the experiment After 30 minutes Diagram 9

3. Based on the observations shown in Diagram 9, suggest a suitable metal to be used in this experiment. Zinc/ magnesium

4. Based on the observations shown in Diagram 9, Predict the ion present in the green solution iron (II) ion

5. The change in oxidation no for both the reactants Change in Ox no of iron is from +3 to +2 ( iron(III) to iron (II) ) Change in Ox no of metal zinc is from 0 to +2 ( zinc to zinc ion) Iron(III) chloride

6. The type of reaction that has occurred to each reactant Iron(III) ion undergoes reduction ( ox no decrease from +3 to +2) Metal atom undergoes oxidation (Ox no increase from 0 to +2) Iron(III) chloride

7. The role of each reactant in the redox reaction Iron(III) ion is an oxidising agent Because it has oxidised zinc to zinc ion Metal is a reducing agent Because it has reduced iron(III) ion to iron(II) ion Iron(III) chloride

8. Half -equations involved in redox reaction For iron (III) chloride, Fe 3+ + e  Fe 2+ For metal zinc, Zn  Zn 2+ + 2e Iron(III) chloride

9. (b) i odide ions are good reducing agent. You are given the following apparatus: U-tube, galvanometer, connecting wires, stopper, dropper, carbon electrodes and retort stand with clamps. Suggest a suitable chemical and describe an experiment to verify the above statement using the given apparatus.

10. Chemicals 1. Oxidising agent such as Acidified KMnO 4 // Acidified K 2 Cr 2 O 7 // Bromine water// chlorine water // iron (III) chloride solution 2. Sulphuric acid as electrolyte 3. Potassium iodide solution

11. Procedure 1. Pour sulphuric acid into U tube untill it reach about 5 cm from the mouth of the U-tube 2. Add potassium iodide solution in one arm of the U tube

12. 3. Add acidified KMnO 4 / or any oxidising agent into the other arm 4.The solutions are added slowly so that they do not mix 5. Dip the graphite electrodes into the two separate solutions and connect it to the galvanometer

13. After 10 minutes, The colour of KMnO 4 changes from purple to colourless MnO 4 - ion is reduced to Mn 2+ ion

14. Colour of potassium iodide solution change to dark brown Iodide ion released electrons to form iodine 2I -  I 2 + 2e Iodide ions has reduced acidified potassium manganate (VII) to manganese ions MnO 4 2- +8H + + 5e  Mn 2+ + 4H 2 O

15. Part 1)SPM 2008 9 (a) A metal M reacts with oxygen to form an oxide. The oxide is very soluble in water to produce an alkaline solution. Suggest the identity of metal M and describe an observation when the metal you have named reacts with oxygen, write the half-equations for oxidation and reduction for the reaction. [4 marks]

16. Metal M is sodium/ potassium / lithium Metal sodium burns brightly with a yellow flame in oxygen to form white fumes which becomes white solid when cooled at room temperature

18. (b) Diagram 9 shows an apparatus set-up to investigate the effect of two different metals, X and Y on the rusting of iron, Fe.

19. The result of this experiment after three days is shown in Table 9. Pair of metals Observation Fe, X Dark blue colour Fe, Y No change

20. Based on Table 9, suggest the identity of metals, X and Y. Give two reasons for each of your choices [6 marks] Dark blue colour shows presence of iron(II) ions. Means iron nail has rusted Metal X is copper/ any metals below iron in ECS Because copper is less electropositive than iron So, copper will encourage iron to rust

21. Based on Table 9, suggest the identity of metals, X and Y. Give two reasons for each of your choices [6 marks] No change means iron nail has not rusted Metal Y is zinc/Magnesium Because zinc/magnesium is more electropositive than iron So, zinc/magnesium will protect iron from rusting

23. Seminar Part 1) SPM 2008 9(C) Iron(II) ions can be converted to iron(III) ions and iron(III) ions can be converted back to iron(II) ions. By using a named metal as a reducing agent and a named halogen as an oxidising agent, describe briefly how you would carry out these two conversions. Describe a test to show that each conversion has taken place. [10 marks]

24. CHANGING OF Fe 2+ TO Fe 3+

25. CHANGING OF Fe 2+ TO Fe 3+ Pour 2 cm 3 of FeSO 4 solution into a test tube. Add chlorine water drop by drop until no further changes. Warm the test tube gently. Add sodium hydroxide solution in excess into the test tube.

26. CHANGING OF Fe 2+ TO Fe 3+ If Fe 3+ present, the colour of the solution turn brown precipitate. OXIDISING AGENT : CHLORINE WATER

27. CHANGING OF Fe 3+ TO Fe 2+

28. CHANGING OF Fe 3+ TO Fe 2+ Pour 2 cm 3 of FeCl 3 solution into a test tube. Add half spatula of Zinc powder into the solution until no further changes. Warm the mixture.

29. CHANGING OF Fe 3+ TO Fe 2+ Filter the mixture using filter funnel and filter paper to remove the excess zinc. The filtrate is then added with excess NaOH solution. If Fe 2+ present, green precipitate is observed. REDUCING AGENT : Zn metal

30. End of part 1