Record your results in a tabular form.

1. List the chemicals required for the experiment described in "The Procedure" section. (0 alama)
2. From Table 8, state the mass of Na$_2$S$_2$O$_3$.5H$_2$O required to prepare 1 L of 0.3 M solution. (1 alama)
3. From Table 7, determine the volume of concentrated H$_2$SO$_4$ to be added to water to make 1 L of 0.2 M H$_2$SO$_4$ solution. (1 alama)
4. From Table 6, state the approximate volume of concentrated HNO$_3$ required to prepare 1 L of 0.4 M HNO$_3$ solution. (1 alama)
5. From Table 5, determine the approximate volume of concentrated HCl (35% purity, 1.18 g/cm$^3$ density) required to prepare 1 L of 1 M HCl solution. (1 alama)
6. Calculate the molarity of the concentrated nitric acid. (3 alama)
7. Using the dilution formula M$_c$V$_c$ = M$_d$V$_d$, calculate the volume of concentrated nitric acid required to prepare 1000 cm$^3$ of 0.5 M HNO$_3$ solution. (2 alama)
8. List the apparatuses needed by the candidate for the Standard Enthalpy of Neutralization experiment. (0 alama)

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The following information is for questions 1 and 2. You are provided with the following: AA: A solution of 0.5 M NH4OH; BB: A solution of 0.1 M HCl; CC: Isobutyl alcohol; and DD: Methyl Orange (MO) indicator. Procedure (i) Using a measuring cylinder, measure 50 cm3 of CC and transfer it into a separating funnel. (ii) Using a measuring cylinder, measure 50 cm3 of AA and pour it into a separating funnel containing CC. (iii) Close the separating funnel and shake the mixture for about two minutes while relieving the pressure in the separating funnel by removing a stopper at intervals of about 30 seconds. Remove the stopper and leave the mixture to settle. (iv) Run the lower aqueous layer into a beaker. (v) Pipette 20 or 25 cm3 of this aqueous layer into a conical flask. Add two drops of MO indicator and note the colour of the mixture. (vi) Titrate the aqueous layer in the flask against solution BB from the burette until there is a colour change. Note the volume of the acid used. (vii) Repeat the titration experiment three times and record your results in a tabular form.

1. List the apparatuses needed by the candidate to determine the enthalpy of solution. (5 alama)
2. Identify the immiscible liquids in this experiment. (2 alama)
3. State two reasons why appearance is important in the identification of ionic compounds. (2 alama)
4. Using the dilution Law (M1V1 = M2V2), calculate the volume of concentrated sulphuric acid needed to prepare 1000 cm3 of 0.5 M solution. (1 alama)
5. List the chemicals needed for this experiment. (2 alama)
6. What is the purpose of shaking the mixture in the separating funnel? (2 alama)
7. Identify the colour of the following ions: (i) Cu2+ (ii) Fe3+ (2 alama)
8. Outline the procedure for determining the enthalpy of solution of ammonium nitrate. (5 alama)
9. Why is it necessary to relieve the pressure in the separating funnel periodically? (2 alama)
10. Add a few drops of 0.1 M potassium ferricyanide solution. (0 alama)
11. Suggest the colour of a compound containing Zn2+ ion. (1 alama)
12. How would you determine the enthalpy of solution for the other salts? (1 alama)
13. What observation would indicate the end point of the titration? (2 alama)
14. Add four drops of potassium thiocyanate solution. (0 alama)
15. Why is it important to record the titre value? (1 alama)
16. Rinse the beaker with distilled water and pour the contents into the volumetric flask; (1 alama)
17. How should the results be recorded? (1 alama)
18. Write down the balanced chemical equation for the reaction between iodine and sodium thiosulphate. (2 alama)
19. Explain the role of the pipette filler. (2 alama)
20. Add a small amount of KI solution to the solution of the sample. Warm and cool the mixture. (0 alama)
21. Suggest one possible source of error in this experiment and how to minimise it. (3 alama)
22. Top up the volumetric flask to the mark by adding more distilled water; and (1 alama)
23. Explain why iodine is used as a connecting path in this titration. (2 alama)
24. Determine the mole ratio between thiosulphate ions and copper(II) ions. (2 alama)
25. How would you determine the distribution coefficient of ammonia between isobutyl alcohol and water in this experiment? (2 alama)
26. Close the volumetric flask and invert it repeatedly to mix the contents thoroughly. (1 alama)
27. What is the dependent variable in this experiment? (1 alama)
28. Suggest two reasons why the experiment is repeated at different temperatures. (2 alama)
29. What is the role of the stopwatch/clock? (1 alama)
30. Calculate the values for 1/T and log 1/t for the experiment conducted at 40 °C. (2 alama)
31. What is the purpose of plotting a graph of log 1/t against 1/T? (1 alama)

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Zn2+ (a) Add a small amount of NaOH/NH4OH solution. ● White precipitate soluble in excess NaOH is formed. Zn2+ present and confirmed. (b) Add two or three drops of 0.1 M Potassiumhexacyanoferrate(II) K4[Fe(CN)6] and stir. ● Bluish white precipitate is formed. Zn2+ present and confirmed.

1. Explain the role of a catalyst in a chemical reaction, referencing the concept of activation energy. (3 alama)
2. Ammonia solution (0 alama)
3. Name the test performed above. (1 alama)
4. MW (0 alama)
5. What is the observation that indicates the presence of nitrate ions? (1 alama)
6. If 25.0 cm3 of 0.1 M NaOH is titrated against a more concentrated HCl solution and 20 cm3 of HCl is used up, what can be inferred about the concentration of the prepared HCl solution? (1 alama)
7. Molarity (0 alama)
8. Name the brown compound formed. (1 alama)
9. % (0 alama)
10. How could the beakers be used in this experiment? (1 alama)
11. S.G. (0 alama)
12. Required volume (mL) (0 alama)

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Ca2+ (a) Add ten drops of 2 M aqueous ammonia to a test solution. (b) Test the acidity of the mixture using the litmus paper. (c) Continue adding ammonia until the mixture is basic. (d) Add about ten drops of 0.2 M ammonium oxalate solution to the mixture. ● White precipitate is formed. ● Ca2+ present and confirmed.

1. Name the test performed above. (1 alama)
2. List the salts provided for the experiment. (1 alama)
3. What is the specified mass of each salt to be used? (1 alama)
4. What observation indicates the presence of sulphate ions? (1 alama)
5. State why dilute HCl is added before adding BaCl2 solution. (1 alama)
6. Give one example of a primary standard reagent. (1 alama)
7. Using the data in Table 10, plot a graph of volume of sodium thiosulphate (y-axis) against time (x-axis). (4 alama)
8. Show the calculation for preparing 1000 cm3 of 0.5 M sulphuric acid from a 18.38 M stock solution using the dilution law. (3 alama)
9. Why is standardization necessary for solutions of non-primary standard reagents? (1 alama)
10. What safety precautions should be taken when handling concentrated sulphuric acid? (1 alama)
11. Deduce the shape of the graph plotted in (d) and explain what it indicates about the reaction rate. (2 alama)
12. Plot a graph of volume of sodium thiosulphate (y-axis) against the reciprocal of time (x-axis). (4 alama)
13. Interpret the shape of the graph plotted in (f) and relate it to the order of the reaction. (3 alama)
14. How would the results change if the concentration of sulphuric acid was doubled? Explain your answer. (2 alama)
15. What is the role of distilled water in step (v)? (1 alama)
16. Suggest two possible sources of error in this experiment. (2 alama)

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Fe2+ Add a few drops of 0.1 M potassium ferricyanide solution. ● Dark blue precipitate is formed. ● Fe2+ is confirmed.

1. Outline the steps for measuring the initial temperature of the water. (1 alama)
2. Describe how to add the ammonium nitrate and start data collection. (1 alama)
3. Explain how temperature data should be recorded after adding the salt. (2 alama)

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Fe3+ Add four drops of potassium thiocyanate solution. ● Deep blood-red precipitate is formed. ● Fe3+ is confirmed.

1. Plot a graph of the reaction time (t) against the temperature (T). Interpret the graph. (0 alama)
2. What are the chemicals used in the Standard Enthalpy of Neutralization experiment? (0 alama)
3. Outline the procedure for standardizing an acid with a standard base. (4 alama)
4. Plot a graph of the reciprocal reaction time (1/t) against the temperature (T). Interpret the graph. (0 alama)
5. What is the importance of the specified concentrations? (0 alama)

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Pb2+ (a) Add small amount of 0.1 M potassium chromate (K2CrO4) solution. ● Yellow precipitate is formed. ● Pb2+ ion is confirmed. (b) Add a small amount of KI solution to the solution of the sample. Warm and cool the mixture. ● Yellow precipitate is formed, which disappears on warming and reappears on cooling. ● Pb2+ present and confirmed.

1. List three factors that affect the rate of a chemical reaction. (1 alama)
2. Briefly explain how one of these factors influences the reaction rate. (2 alama)

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3.4 Two Component Liquid Systems If a substance is soluble in two liquids which are completely immiscible, it will distribute itself between the two liquids in such a way that the ratio of its concentration in the two liquids is constant. The distribution coefficient of the substance between two immiscible liquids is then calculated using the following relationship: Distribution coefficient = Concentration of solute in aqueous layer / Concentration of solute in organic layer For example, ammonia distributes itself between water and isobutyl alcohol until the ratio of concentration of NH3 becomes constant. Distribution coefficient = Concentration of NH3 in aqueous layer / Concentration of NH3 in isobutyl alcohol

1. Explain the principle and general procedure for identifying cations and anions in a single salt using group separation. (5 alama)

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When NaOH/NH4OH solution is added to a sample solution containing Zn2+, a white precipitate is formed which is soluble in excess. What is the next confirmatory test for Zn2+?

A white precipitate is formed when aqueous ammonia is added to a test solution. What is the cation if the precipitate is insoluble in excess ammonia?

The following are procedures for qualitative analysis of ions: (i) Add dilute sodium hydroxide solution drop by drop to a test solution. Stir or shake the mixture and observe any reaction. If the precipitate forms continue, add sodium hydroxide solution in excess. If no precipitation is formed, warm the mixture. (ii) Add dilute aqueous ammonia drop by drop to a test solution. Stir or shake the mixture and observe any reaction. If a precipitate forms, continue adding aqueous ammonia. (a) Identify the type of ions being tested for in procedure (i) and (ii). Explain your answer. (b) Mention two observations that can be made from procedure (i) and state the possible cations corresponding to these observations.

1. Identify the type of ions being tested for in procedure (i) and (ii). Explain your answer. (2 alama)
2. 1. Prepare a paste by mixing about 10 g of soluble starch powder with about 100 mL of deionized water. 2. Pour the paste into 900 mL of boiling distilled water in a beaker. 3. Boil the mixture gently for about 5 minutes, stirring continuously until all the starch dissolves. 4. Allow the solution to cool down. If a precipitate forms, decant the clear supernatant liquid for use as the indicator. (4 alama)
3. Mention two observations that can be made from procedure (i) and state the possible cations corresponding to these observations. (3 alama)

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Table 16 shows a sample presentation of results for confirmatory tests for cations. Cation | Procedure | Observation/inferences -------|-----------|------------------------ Cu2+ | (a) To a sample solution, ammonia solution is added in excess. (b) To a sample solution, Potassium Ferrocyanide solution is added. | (a) Pale blue precipitate is formed soluble in excess ammonia to form deep blue solution. Cu2+ present and confirmed. (b) Reddish brown gelatinous precipitate is formed soluble in aqueous ammonia but insoluble in aqueous mineral acids. Cu2+ is present and confirmed. NH4+ | Add NaOH solution to a small amount of solid sample and warm it, pass moist litmus paper to the mouth of the test tube. Dip a glass rod in concentrated HCl and pass it to the mouth of a test tube containing the mixture. | Colourless gas which turns moist red litmus paper blue and forms white fumes with concentrated HCl evolves. NH4+ present and confirmed. Zn2+ | (a) Add a small amount of NaOH/NH4OH solution. (b) Add two or three drops of 0.1 M Potassiumhexacyanoferrate(II) K4[Fe(CN)6] and stir. | (a) White precipitate soluble in excess NaOH is formed. Zn2+ present and confirmed. (b) Bluish white precipitate is formed. Zn2+ present and confirmed. Ca2+ | (a) Add ten drops of 2 M aqueous ammonia to a test solution. (b) Test the acidity of the mixture | (a) White precipitate is formed.

1. For the test of Cu2+ using ammonia solution, explain why the precipitate formed is soluble in excess ammonia. (2 alama)
2. Calculate the molarity of the solution prepared from the hexahydrated salt. (0 alama)
3. 10% (w/v) means that there are 10 grams of solute (KI) dissolved in every 100 mL of solution. (1 alama)
4. For 10% (w/v), 10 g of KI is dissolved in 100 mL of solution. For 250 mL of solution, mass of KI required = (10 g / 100 mL) * 250 mL = 25 g (2 alama)
5. Write the ionic equation for the reaction that occurs when potassium ferrocyanide is added to a solution containing Zn2+ ions. (2 alama)
6. 1. Weigh accurately 25 g of Potassium Iodide (KI). 2. Dissolve the KI in a small amount of distilled water in a beaker. 3. Transfer the solution to a 250 mL volumetric flask. 4. Rinse the beaker with a small amount of distilled water and add the rinsings to the flask. 5. Add distilled water to the mark (250 mL), stopper the flask, and mix thoroughly. (2 alama)
7. Describe the expected observation in procedure (b) for the test of Ca2+ if the test solution contains sulfate ions. (2 alama)

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Calcium sulphate solution is prepared by shaking 2.04 g of the salt with 1 litre of water, filter and decant the saturated solution after several hours. Calculate the molarity of the saturated solution.

1. Calculate the molarity of the saturated solution. (0 alama)

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Chlorine water is prepared by saturating 250 mL of water with chlorine. The chlorine may be prepared by dropping conc. HCl upon KMnO₄. The concentration of the chlorine water is 6.8 g/l. Calculate the number of moles of chlorine gas present in 250 mL of this solution.

1. Calculate the number of moles of chlorine gas present in 250 mL of this solution. (0 alama)

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Cobalt nitrate solution is prepared by dissolving 44 g of the hexahydrate salt or 27.5 g of anhydrous to make 1 litre of solution. Calculate the molarity of the solution prepared from the anhydrous salt.

1. Calculate the molarity of the solution prepared from the anhydrous salt. (0 alama)

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Copper sulphate solution is prepared by dissolving 125 g of the hydrated salt or 80 g of anhydrous salt in 1 litre of water containing 3 mL of the conc. sulphuric acid. Calculate the molarity of the solution prepared from the anhydrous salt.

1. Calculate the molarity of the solution prepared from the anhydrous salt. (0 alama)
2. Explain the note concerning the addition of acid to water. (2 alama)

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Ferric chloride solution is prepared by dissolving 135.2 g of FeCl₃.6H₂O in water containing 20 mL of the concentrated HCl, dilute to 1 L with water and filter if necessary. Calculate the molarity of the solution prepared from the hydrated ferric chloride.

1. Calculate the molarity of the solution prepared from the hydrated ferric chloride. (0 alama)

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Ferrous sulphate solution is prepared by dissolving 139 g of ferrous sulphate heptahydrate or 76 g of anhydrous ferrous sulphate in water containing 7 ml of the concentrated sulphuric acid to make 1 L of solution. Calculate the molarity of the solution prepared from the anhydrous ferrous sulphate.

1. Calculate the molarity of the solution prepared from the anhydrous ferrous sulphate. (0 alama)

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Hydrogen sulphide (H₂S) is generated from a Kipps apparatus. The concentration of the gas in solution is approximately 42 g/l. Calculate the molarity of the hydrogen sulphide solution.

1. Calculate the molarity of the hydrogen sulphide solution. (0 alama)

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Iodine solution is prepared by dissolving 12.7 g of iodine in a solution of 20 g of pure KI in 30 mL of water, and dilute it to 1 litre of solution. Calculate the molarity of the iodine solution.

1. Calculate the molarity of the iodine solution. (0 alama)

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Lead acetate solution is prepared by dissolving 95 g of Pb(C₂H₃O₂)₂.3H₂O to make 1 L water. Add sufficient dilute acetic acid to clear the solution. Calculate the molarity of the lead acetate solution.

1. Calculate the molarity of the lead acetate solution. (0 alama)

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Magnesium sulphate solution is prepared by dissolving 62 g of MgSO₄.7H₂O in 1000 mL water. Calculate the molarity of the magnesium sulphate solution.

1. Calculate the molarity of the magnesium sulphate solution. (0 alama)

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Potassium chromate solution is prepared by dissolving 49 g of the salt to make 1 litre of solution. Calculate the molarity of the potassium chromate solution.

1. Calculate the molarity of the potassium chromate solution. (0 alama)

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Potassium dichromate solution is prepared by dissolving 35 g of the salt to make 1 litre of solution. Calculate the molarity of the potassium dichromate solution.

1. Calculate the molarity of the potassium dichromate solution. (0 alama)

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Potassium ferricyanide: Dissolve 55 g of the salt to make 1 litre of solution. Concentration 0.167 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Potassium ferrocyanide: Dissolve 53 g K4Fe(CN)6.6H2O of the salt to make 1 litre of solution. Concentration 0.125 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Potassium iodide: Dissolve 83 g of the salt to make 1 litre of solution. Concentration 0.5 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Potassium permanganate: Dissolve 1.58 g of the salt in hot water, dilute to 1 litre, and filter through glass wool. Concentration 0.01 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Potassium hexacyanoferrate(II): Dissolve 105 g of the salt to make 1 litre of solution. Concentration 0.25 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Potassium thiocyanate: Dissolve 48.5 g of the salt to make 1 litre of solution. Concentration 0.5 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Silver nitrate: Dissolve 17 g of the salt to make 1 litre of solution. Concentration 0.1 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Sodium acetate: Dissolve 408 g of the salt to make 1 litre of solution. Concentration 3 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Sodium carbonate: Dissolve 429 g of the decahydrate salt or 159 g of the anhydrous salt to make 1 litre of solution. Concentration 1.5 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Zinc nitrate: Dissolve 94.7 g of the salt to make 1 litre of solution. Concentration 0.5 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Sodium hydroxide: Dissolve 200 g of the salt to make 1 litre of solution. Concentration 5 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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Silver nitrate: Dissolve 43 g of the salt to make 1 litre of solution. Concentration 0.25 M

1. Name of the Reagent (0 alama)
2. How to prepare it (0 alama)
3. Concentration (0 alama)

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