📋 Instructions

Time allowed: 30 minutes

Total marks: 20

• Answer ALL questions in the spaces provided

• For multiple choice questions, circle the correct answer

• Show your working where appropriate

• Use a pen or pencil

🧪 Part A: Multiple Choice Questions

1. Which of the following is NOT a physical property? (1 mark)

a) Melting point

b) Density

c) Flammability

d) Colour

2. What is the chemical symbol for sodium? (1 mark)

a) S

b) So

c) Na

d) Sd

3. How many electrons does a neutral carbon atom have? (1 mark)

a) 4

b) 6

c) 8

d) 12

4. Which state of matter has particles that are closely packed but can move past each other? (1 mark)

a) Solid

b) Liquid

c) Gas

d) Plasma

✏️ Part B: Short Answer and Application Questions

5. Define what an element is in chemistry. (2 marks)

6. Label the diagram of an atom below by filling in the blanks: (4 marks)

Draw or imagine a simple atom diagram with nucleus and electron shells

A: __________ (centre of atom)

B: __________ (positive particles in centre)

C: __________ (neutral particles in centre)

D: __________ (negative particles orbiting)

7. Balance the following chemical equation: (3 marks)

___H₂ + ___O₂ → ___H₂O

8. A student heats 50g of water from 20°C to 80°C. Calculate the temperature change and explain whether this is a physical or chemical change. Show your working. (7 marks)

📝 Answer Key

Part A: Multiple Choice

1. c) Flammability (1 mark)

2. c) Na (1 mark)

3. b) 6 (1 mark)

4. b) Liquid (1 mark)

Part B: Short Answer

5. An element is a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom. (2 marks)

6. A: Nucleus, B: Protons, C: Neutrons, D: Electrons (1 mark each = 4 marks)

7. 2H₂ + 1O₂ → 2H₂O (3 marks - 1 mark for each correct coefficient)

8. Temperature change = 80°C - 20°C = 60°C (2 marks)
This is a physical change because no new substances are formed - the water molecules remain the same, only their kinetic energy increases. (5 marks - 2 for calculation, 3 for explanation)

Total: 20 marks