(x) The gas that forms a white precipitate with lime water is: A. Oxygen B. Hydrogen C. Carbon dioxide D. Nitrogen

Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided. LIST A LIST B (i) Gas used in welding A. Nitrogen (ii) Prevents rusting by coating iron B. Zinc (iii) Separates liquids with different boiling points C. Fractional distillation (iv) Element with atomic number 12 D. Magnesium (v) Turns brown in iodine test E. Starch (vi) Apparatus for heating solids F. Crucible (vii) Liquid used in thermometers G. Mercury (viii) Method to obtain pure water H. Distillation (ix) Gas that does not support combustion I. Carbon dioxide (x) Supports combustion J. Oxygen

1. Gas used in welding (1 mk)
2. Gas used in welding (1 mk)
3. Prevents rusting by coating iron (1 mk)
4. Prevents rusting by coating iron (1 mk)
5. Separates liquids with different boiling points (1 mk)
6. Separates liquids with different boiling points (1 mk)
7. Element with atomic number 12 (1 mk)
8. Element with atomic number 12 (1 mk)
9. Turns brown in iodine test (1 mk)
10. Turns brown in iodine test (1 mk)
11. Apparatus for heating solids (1 mk)
12. Apparatus for heating solids (1 mk)
13. Liquid used in thermometers (1 mk)
14. Method to obtain pure water (1 mk)
15. Method to obtain pure water (1 mk)
16. Gas that does not support combustion (1 mk)
17. Gas that does not support combustion (1 mk)
18. Supports combustion (1 mk)
19. Supports combustion (1 mk)

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Define the term "atom". Name three subatomic particles found in an atom. State the charge and location of each particle named in (b).

1. Define the term "atom". (2 mk)
2. Name three subatomic particles found in an atom. (2 mk)
3. State the charge and location of each particle named in (b). (3 mk)

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What is meant by the term "ionic bond"? Draw diagrams to show the electron arrangement in: (i) A fluorine atom (atomic number 9) (ii) A fluoride ion State the type of bond formed between magnesium and oxygen.

1. What is meant by the term "ionic bond"? (2 mk)
2. Draw diagrams to show the electron arrangement in: (i) A fluorine atom (atomic number 9) (ii) A fluoride ion (3 mk)
3. State the type of bond formed between magnesium and oxygen. (2 mk)

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Define the term "solution". List three differences between a solution and a suspension. Name one method to separate a solution of sugar and water.

1. Define the term "solution". (2 mk)
2. List three differences between a solution and a suspension. (3 mk)
3. Name one method to separate a solution of sugar and water. (2 mk)

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a) What is meant by the term "fire triangle"? (b) State three components of the fire triangle. (c) Name one method to extinguish a fire caused by burning paper.

1. What is meant by the term "fire triangle"? (0 mk)
2. State three components of the fire triangle. (0 mk)
3. Name one method to extinguish a fire caused by burning paper. (0 mk)

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a) Define the term "valency". (b) Calculate the oxidation number of the underlined elements: (i) Na₂SO₄ (S underlined) (ii) HClO₄ (Cl underlined) (c) State one example of a reduction reaction in daily life.

1. Define the term "valency". (0 mk)
2. Calculate the oxidation number of the underlined elements: (i) Na₂SO₄ (S underlined) (ii) HClO₄ (Cl underlined) (0 mk)
3. State one example of a reduction reaction in daily life. (0 mk)

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a) What is meant by the term "first aid"? (b) List three items found in a first aid kit in a chemistry laboratory. (c) State one use of a splint in first aid.

1. What is meant by the term "first aid"? (0 mk)
2. List three items found in a first aid kit in a chemistry laboratory. (0 mk)
3. State one use of a splint in first aid. (0 mk)

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a) Define the term "oxygen". (b) Describe a laboratory test for oxygen gas. (c) Name one use of oxygen in everyday life.

1. Define the term "oxygen". (0 mk)
2. Describe a laboratory test for oxygen gas. (0 mk)
3. Name one use of oxygen in everyday life. (0 mk)

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a) What is meant by the term "non-renewable resource"? (b) Name two non-renewable fuels used in Tanzania. (c) State one environmental impact of using non-renewable fuels.

1. What is meant by the term "non-renewable resource"? (0 mk)
2. Name two non-renewable fuels used in Tanzania. (0 mk)
3. State one environmental impact of using non-renewable fuels. (0 mk)

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