The purpose of filtration in water treatment is to: A. Remove dissolved salts B. Kill bacteria C. Remove solid particles D. Add flavor

Match each item in List A with a correct response in List B by writing its letter against the appropriate statement in the space provided. LIST A (i) Gas that supports burning (ii) Process of separating salt from water (iii) Element with atomic number 11 (iv) Apparatus for heating liquids (v) Gas that produces a pop sound (vi) Prevents rust by coating iron (vii) Liquid at room temperature (viii) Separates immiscible liquids (ix) Turns litmus paper red (x) Method to test for starch LIST B A. Evaporation B. Oxygen C. Sodium D. Beaker E. Hydrogen F. Galvanization G. Mercury H. Separating funnel I. Acid J. Iodine solution

1. Gas that supports burning (1 alama)
2. Process of separating salt from water (1 alama)
3. Element with atomic number 11 (1 alama)
4. Apparatus for heating liquids (1 alama)
5. Gas that produces a pop sound (1 alama)
6. Prevents rust by coating iron (1 alama)
7. Liquid at room temperature (1 alama)
8. Separates immiscible liquids (1 alama)
9. Turns litmus paper red (1 alama)
10. Method to test for starch (1 alama)

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Find the oxidation state or number of the following underlined elements: (i) Na: (ii) CO₃²⁻ (C underlined): (iii) H₂SO₄ (S underlined): (iv) K₂CrO₄ (Cr underlined):

1. Define the term acid. (0 alama)
2. (iii) Phenolphthalein (0 alama)
3. Litmus (2 alama)
4. Methyl Orange (2 alama)
5. (iv) K₂CrO₄ (Cr underlined): (0 alama)
6. Phenolphthalein (2 alama)
7. Na: (1 alama)
8. CO₃²⁻ (C underlined): (1 alama)
9. H₂SO₄ (S underlined): (1 alama)
10. K₂CrO₄ (Cr underlined): (1 alama)

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Define the following: (i) Base: (ii) Mixture:

1. Mention four laboratory safety rules. (0 alama)
2. Which element has a higher ionization energy? (1 alama)
3. (ii) Mixture: (0 alama)
4. Of the two elements, which one has larger atoms? (1 alama)
5. Which type of bond forms when element X combines with hydrogen? (1 alama)
6. (iv) Find the charge of atom X after the reaction in question (iii). (0 alama)
7. Find the charge of atom X after the reaction in question (iii). (1 alama)

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3. (a) What is an element? (b) Mention three elements found in everyday life. (c) Write the names of the following processes of changing matter from one state to another: (i) Liquid to solid: (ii) Solid to gas: (iii) Gas to solid:

1. What is an element? (1 alama)
2. Mention three elements found in everyday life. (3 alama)
3. Liquid to solid: (1 alama)
4. Write the names of the following processes of changing matter from one state to another: (3 alama)
5. Liquid to solid: (1 alama)
6. Gas to solid: (1 alama)
7. Solid to gas: (1 alama)
8. Gas to solid: (1 alama)

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4. (a) Write the chemical symbols for the following: (i) Iron: (ii) Sulphur: (iii) Silver: (iv) Calcium: (v) Nitrogen: (b) Write the formulae for the following compounds: (i) Sodium chloride: (ii) Carbon dioxide: (iii) Magnesium sulphate: (iv) Water: (v) Ammonia: (c) Write balanced equations for the following chemical reactions: (i) Sodium + Water → Sodium hydroxide + Hydrogen (ii) Burning of carbon in oxygen (iii) Calcium hydroxide + Nitric acid → Calcium nitrate + Water (iv) Zinc + Hydrochloric acid → Zinc chloride + Hydrogen (v) Decomposition of copper(II) carbonate

1. Iron: (1 alama)
2. Write the chemical symbols for the following: (5 alama)
3. Iron: (1 alama)
4. Sulphur: (1 alama)
5. Silver: (1 alama)
6. Silver: (1 alama)
7. Calcium: (1 alama)
8. Nitrogen: (1 alama)
9. Calcium: (1 alama)
10. Nitrogen: (1 alama)
11. Sodium chloride: (1 alama)
12. Write the formulae for the following compounds: (5 alama)
13. Sodium chloride: (1 alama)
14. Magnesium sulphate: (1 alama)
15. Water: (1 alama)
16. Carbon dioxide: (1 alama)
17. Ammonia: (1 alama)
18. Magnesium sulphate: (1 alama)
19. Sodium + Water → Sodium hydroxide + Hydrogen (2 alama)
20. Water: (1 alama)
21. Ammonia: (1 alama)
22. Calcium hydroxide + Nitric acid → Calcium nitrate + Water (2 alama)
23. Write balanced equations for the following chemical reactions: (6 alama)
24. Zinc + Hydrochloric acid → Zinc chloride + Hydrogen (2 alama)
25. Sodium + Water → Sodium hydroxide + Hydrogen (1 alama)
26. Burning of carbon in oxygen (1 alama)
27. Calcium hydroxide + Nitric acid → Calcium nitrate + Water (1 alama)
28. Zinc + Hydrochloric acid → Zinc chloride + Hydrogen (1 alama)
29. Decomposition of copper(II) carbonate (2 alama)

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Write three differences between a homogeneous and a heterogeneous mixture.

1. Write three differences between a homogeneous and a heterogeneous mixture. (0 alama)
2. Oil mixed with water: (1 alama)
3. Write three differences between a homogeneous and a heterogeneous mixture. (3 alama)
4. Sugar mixed with sand: (1 alama)
5. Iodine mixed with sodium chloride: (1 alama)
6. (iv) Ethanol mixed with water: (0 alama)
7. Ethanol mixed with water: (1 alama)

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What is the use of the following apparatus? (i) Evaporating dish: (ii) Spatula: (iii) Bunsen burner: (iv) Measuring cylinder: (v) Fume cupboard:

1. Evaporating dish: (1 alama)
2. Spatula: (1 alama)
3. Bunsen burner: (1 alama)
4. Measuring cylinder: (1 alama)
5. Fume cupboard: (1 alama)
6. (v) 2KClO₃(s) → 2KCl(s) + 3O₂(g): (0 alama)
7. (v) Fume cupboard: (0 alama)

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Define the following: (i) Base: (ii) Mixture:

1. Base: (1 alama)
2. Mixture: (1 alama)

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State any three uses of oxygen.

1. Draw a well labelled diagram of preparation of oxygen gas. (0 alama)
2. What is the test for oxygen gas? (0 alama)
3. State any three uses of oxygen. (0 alama)
4. Draw a well labelled diagram of preparation of oxygen gas. (4 alama)
5. What is the test for oxygen gas? (2 alama)
6. State any three uses of oxygen. (3 alama)

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What do you understand by the following chemical warning terms? (i) Corrosive: (ii) Toxic: (iii) Irritant: (iv) Oxidizing:

1. Define the term fuel. (2 alama)
2. Write down three examples of fuels used in Tanzania. (3 alama)
3. Explain why a non-luminous flame is preferred for heating. (3 alama)
4. Corrosive: (1 alama)
5. Toxic: (1 alama)
6. Irritant: (1 alama)
7. Oxidizing: (1 alama)

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