Welcome to Bodhiclasses, your trusted platform for insightful and exam-ready study materials. We aim to simplify science for learners of all levels by offering easy-to-understand content, worksheets, and assessments. This post is a sample question paper of NCERT Class 7 Science Chapter 5: Changes Around Us, that would clear your concepts, test your understanding and make you ready for examinations.
Maximum Marks: 40 | Time: 1 Hour
SECTION A: Multiple Choice Questions (1 mark each) | Changes Around Us
(Attempt all questions)
Q1. Which of the following is a physical change?
A. Rusting of iron
B. Melting of wax
C. Burning of paper
D. Curdling of milk
Q2. Which of the following is not needed for combustion?
A. Oxygen
B. Heat
C. Fuel
D. Water
Q3. Lime water turns milky due to the presence of:
A. Oxygen
B. Carbon dioxide
C. Hydrogen
D. Nitrogen
Q4. Which of the following is a chemical change?
A. Boiling water
B. Melting wax
C. Burning magnesium
D. Folding paper
Q5. The brown substance formed on iron is:
A. Iron sulphate
B. Iron nitrate
C. Iron oxide
D. Iron chloride
Q6. A change that forms a new substance is called:
A. Physical
B. Reversible
C. Chemical
D. Temporary
Q7. Which of the following changes is reversible?
A. Rusting
B. Cooking
C. Folding a cloth
D. Burning wood
Q8. The gas evolved during the reaction of vinegar and baking soda is:
A. Oxygen
B. Carbon dioxide
C. Methane
D. Nitrogen
Q9. Which part of the fire triangle provides heat?
A. Oxygen
B. Fuel
C. Combustible material
D. Ignition source
Q10. Which of the following involves both physical and chemical changes?
A. Melting ice
B. Burning a candle
C. Dissolving salt
D. Crushing chalk
SECTION B: Very Short Answer Questions (1 mark each) | Changes Around Us
(Answer in one sentence)
Q11. Define ignition temperature.
Q12. Is melting of ice reversible or irreversible?
Q13. Name one undesirable change that occurs in metals.
Q14. Write one example of a desirable chemical change.
Q15. What change is observed when lime water is exposed to CO₂?
SECTION C: Short Answer Questions (2 marks each)
(Answer in 30–40 words)
Q16. What are the three requirements for combustion?
Q17. Why is burning of magnesium considered a chemical change?
Q18. Distinguish between physical and chemical changes with examples.
Q19. What is weathering? Mention one physical and one chemical cause.
Q20. Explain why cutting fruits is a physical change while ripening of fruits is a chemical change.
SECTION D: Higher Order Thinking Skills (3 marks each)
(Answer briefly with explanation)
Q21. You are given water and alcohol. Both are clear liquids. How will you prove which one is combustible without drinking or smelling them?
Q22. Paper can be burnt in air but does not catch fire on its own. Explain why.
Q23. A student placed a steel spoon in water for many days. After some time, it turned reddish-brown. Explain the change and suggest one way to prevent it.
Q24. How does composting reflect a chemical change? Why is it desirable?
Q25. Give reasons: (a) We use water to extinguish fire. (b) Fire requires continuous oxygen supply.
Sample Question Paper: Changes Around Us – Answer Key
SECTION A: MCQs
- B
- D
- B
- C
- C
- C
- C
- B
- D
- B
SECTION B: Very Short Answers
- The minimum temperature at which a substance catches fire.
- Reversible.
- Rusting.
- Making curd from milk.
- It turns milky.
SECTION C: Short Answers
- Fuel, oxygen, and heat (to reach ignition temperature).
- Because it forms a new substance (magnesium oxide) and releases heat and light.
- Physical change: No new substance (e.g., melting ice). Chemical change: New substance formed (e.g., burning wood).
- Weathering is the breaking down of rocks. Physical: wind, temperature. Chemical: reaction with water or air.
- Cutting changes only shape – physical; ripening forms new chemicals – chemical.
SECTION D: HOTS
- Try to ignite a small quantity of both. Alcohol is combustible and will catch fire; water will not.
- Paper needs heat to reach ignition temperature. A matchstick provides that heat.
- It is rusting, a chemical change. It can be prevented by painting or oiling.
- Composting turns organic waste into manure via bacteria – a chemical change, desirable for soil health.
- (a) Water lowers temperature below ignition point. (b) Oxygen is essential for fire to continue burning.
