Class 10 Science: Chemical Reactions and Equations Question Paper

Section A – Very Short Answer Questions (1 × 5 = 5 Marks)

(Answer each question in one sentence)

1. Define a chemical reaction.

2. Give one example each of an exothermic and an endothermic reaction.

3. What is the difference between a physical change and a chemical change?

4. Name the gas evolved when zinc reacts with sulphuric acid.

5. Write the chemical equation for rusting of iron.

Section B – Short Answer Questions – I (2 × 5 = 10 Marks)

6. State any two indicators that a chemical reaction has taken place with examples.

7. Differentiate between balanced and unbalanced chemical equations. Give one example of each.

8. Write the balanced chemical equation for:

   • (a) Combustion of methane (CH₄)

   • (b) Reaction of zinc with HCl

9. What is rancidity? Mention two methods to prevent it.

10. Write one example each of:

• (a) Combination reaction

• (b) Decomposition reaction

Section C – Short Answer Questions – II (3 × 5 = 15 Marks)

11. Explain with an example how precipitate formation indicates a chemical change.

12. Balance the following chemical equation step by step:
    Fe + H₂O → Fe₃O₄ + H₂

13. What is a redox reaction? Explain with one balanced chemical equation.

14. Differentiate between displacement and double displacement reactions with examples.

15. Give reasons:

• (a) Respiration is considered an exothermic reaction.

• (b) Cooking oil is kept in airtight containers.

• (c) Food is packed in nitrogen gas.

Section D – Long Answer Questions (5 × 4 = 20 Marks)

16. (a) What is meant by a balanced chemical equation? Why should a chemical equation be balanced?
    (b) Write the steps involved in balancing a chemical equation with the example of Fe + H₂O → Fe₃O₄ + H₂.

17. (a) Explain with examples the difference between exothermic and endothermic reactions.
    (b) Show with the help of an equation how energy is released during a thermite reaction.

18. (a) Define corrosion. Write the chemical reaction involved in the rusting of iron.
    (b) Write two methods of preventing corrosion and rancidity.

19. Write short notes on the following with examples:

• (a) Combination Reaction

• (b) Decomposition Reaction

• (c) Displacement Reaction

• (d) Double Displacement Reaction

20. A reaction is carried out between Fe²⁺ and Cr₂O₇²⁻ in acidic medium. Write the steps of balancing the reaction using the redox method.

Follow us on facebook for all classes question papers and solutions.