The gas used in balloons is:

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 (i) Gas that produces a pop sound (ii) Coating iron with paint (iii) Separates solids from liquids (iv) Element with atomic number 16 (v) Forms blue solution with copper(II) sulphate (vi) Apparatus for precise liquid dispensing (vii) Liquid used in batteries (viii) Method to obtain sugar from solution (ix) Gas used in fire extinguishers (x) Element in group I, period 3 LIST B A. Oxygen B. Rust prevention C. Filtration D. Sulphur E. Water F. Pipette G. Sulphuric acid H. Evaporation I. Carbon dioxide J. Sodium

1. Gas that produces a pop sound (1 mk)
2. Gas that produces a pop sound (1 mk)
3. Coating iron with paint (1 mk)
4. Coating iron with paint (1 mk)
5. Separates solids from liquids (1 mk)
6. Separates solids from liquids (1 mk)
7. Element with atomic number 16 (1 mk)
8. Element with atomic number 16 (1 mk)
9. Forms blue solution with copper(II) sulphate (1 mk)
10. Forms blue solution with copper(II) sulphate (1 mk)
11. Apparatus for precise liquid dispensing (1 mk)
12. Apparatus for precise liquid dispensing (1 mk)
13. Liquid used in batteries (1 mk)
14. Liquid used in batteries (1 mk)
15. Method to obtain sugar from solution (1 mk)
16. Method to obtain sugar from solution (1 mk)
17. Gas used in fire extinguishers (1 mk)
18. Gas used in fire extinguishers (1 mk)
19. Element in group I, period 3 (1 mk)
20. Element in group I, period 3 (1 mk)

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(a) Define the term "molecule". (b) Name three types of chemical bonds. (c) Give one example of a compound formed by each bond type in (b).

1. Define the term "molecule". (2 mk)
2. Define the term "molecule". (2 mk)
3. Name three types of chemical bonds. (3 mk)
4. Name three types of chemical bonds. (3 mk)
5. Give one example of a compound formed by each bond type in (b). (2 mk)
6. Give one example of a compound formed by each bond type in (b). (2 mk)

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(a) What is meant by the term "covalent bond"? (b) Draw diagrams to show the electron arrangement in: (i) A nitrogen atom (atomic number 7) (ii) A nitrogen molecule (N₂) (c) State the type of bond formed between hydrogen and oxygen in water.

1. What is meant by the term "covalent bond"? (2 mk)
2. What is meant by the term "covalent bond"? (2 mk)
3. Draw diagrams to show the electron arrangement in: (i) A nitrogen atom (atomic number 7) (ii) A nitrogen molecule (N₂) (3 mk)
4. Draw diagrams to show the electron arrangement in: (i) A nitrogen atom (atomic number 7) (ii) A nitrogen molecule (N₂) (3 mk)
5. State the type of bond formed between hydrogen and oxygen in water. (2 mk)
6. State the type of bond formed between hydrogen and oxygen in water. (2 mk)

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(a) Define the term "suspension". (b) List three properties of a suspension. (c) Name one method to separate mud from muddy water.

1. Define the term "suspension". (2 mk)
2. Define the term "suspension". (2 mk)
3. List three properties of a suspension. (3 mk)
4. List three properties of a suspension. (3 mk)
5. Name one method to separate mud from muddy water. (2 mk)
6. Name one method to separate mud from muddy water. (2 mk)

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(a) What is meant by the term "extinguisher"? ............................................................................................................................................................. ............................................................................................................................................................. (b) Name three types of fire extinguishers. ............................................................................................................................................................. ............................................................................................................................................................. (c) State one precaution when using a water extinguisher. ............................................................................................................................................................. .............................................................................................................................................................

1. What is meant by the term "extinguisher"? (1 mk)
2. What is meant by the term "extinguisher"? (2 mk)
3. Name three types of fire extinguishers. (3 mk)
4. Name three types of fire extinguishers. (3 mk)
5. State one precaution when using a water extinguisher. (2 mk)
6. State one precaution when using a water extinguisher. (1 mk)

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(a) Define the term "isotope". ............................................................................................................................................................. ............................................................................................................................................................. (b) Calculate the number of neutrons in: (i) Carbon-12 (atomic number 6) (ii) Carbon-14 (atomic number 6) ............................................................................................................................................................. ............................................................................................................................................................. (c) State one use of isotopes in science. ............................................................................................................................................................. .............................................................................................................................................................

1. Define the term "isotope". (1 mk)
2. Define the term "isotope". (2 mk)
3. Calculate the number of neutrons in: (i) Carbon-12 (atomic number 6) (ii) Carbon-14 (atomic number 6) (3 mk)
4. Calculate the number of neutrons in: (i) Carbon-12 (atomic number 6) (ii) Carbon-14 (atomic number 6) (2 mk)
5. State one use of isotopes in science. (2 mk)
6. State one use of isotopes in science. (2 mk)

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(a) What is meant by the term "hazard symbol"? ............................................................................................................................................................. ............................................................................................................................................................. (b) List three hazard symbols found in a chemistry laboratory. ............................................................................................................................................................. ............................................................................................................................................................. (c) State the meaning of one symbol listed in (b). 5

1. What is meant by the term "hazard symbol"? (1 mk)
2. What is meant by the term "hazard symbol"? (2 mk)
3. List three hazard symbols found in a chemistry laboratory. (3 mk)
4. List three hazard symbols found in a chemistry laboratory. (3 mk)
5. State the meaning of one symbol listed in (b). (1 mk)
6. State the meaning of one symbol listed in (b). (2 mk)

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(a) Define the term "hydrogen". ............................................................................................................................................................. ............................................................................................................................................................. (b) Describe a laboratory test for hydrogen gas. ............................................................................................................................................................. ............................................................................................................................................................. (c) Name one industrial use of hydrogen. ............................................................................................................................................................. .............................................................................................................................................................

1. Define the term "hydrogen". (1 mk)
2. Describe a laboratory test for hydrogen gas. (2 mk)
3. Name one industrial use of hydrogen. (2 mk)

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(a) What is meant by the term "water hardness"? ............................................................................................................................................................. ............................................................................................................................................................. (b) Name two types of water hardness. ............................................................................................................................................................. ............................................................................................................................................................. (c) State one method to remove temporary hardness from water. ............................................................................................................................................................. ............................................................................................................................................................. ............................................................................................................................................................. ............................................................................................................................................................. ............................................................................................................................................................. ............................................................................................................................................................. 6

1. What is meant by the term "water hardness"? (1 mk)
2. Name two types of water hardness. (2 mk)
3. State one method to remove temporary hardness from water. (2 mk)

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