WILLER ACADEMY

Class 10 Science Chapter 1 Quiz

Chemical Reactions and Equations

1. Which of the following is a balanced chemical equation?
a) H₂ + O₂ → H₂O b) 2H₂ + O₂ → 2H₂O c) H₂ + O₂ → 2H₂O d) 2H₂ + 2O₂ → 2H₂O

2. What type of reaction is represented by: 2KClO₃ → 2KCl + 3O₂
a) Combination b) Decomposition c) Displacement d) Double displacement

3. Which reaction is an example of a displacement reaction?
a) Zn + CuSO₄ → ZnSO₄ + Cu b) AgNO₃ + NaCl → AgCl + NaNO₃ c) C + O₂ → CO₂ d) CaCO₃ → CaO + CO₂

4. Which of the following is an example of oxidation?
a) Fe + O₂ + H₂O → Fe₂O₃·xH₂O b) AgNO₃ + NaCl → AgCl + NaNO₃ c) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl d) Zn + H₂SO₄ → ZnSO₄ + H₂

5. Which statement is correct about a chemical equation?
a) It must always be balanced b) It need not show physical states c) It can have unequal atoms on both sides d) It never shows products

6. Define a chemical reaction. Give one example. (2 marks)

7. What is meant by a balanced chemical equation? Why should chemical equations be balanced? (2 marks)

8. Balance the following chemical equation and identify the type of reaction:
Fe + H₂O → Fe₃O₄ + H₂ (3 marks)

9. Write any three differences between a displacement and a double displacement reaction. (3 marks)

10.
a) Explain the following types of chemical reactions with one example each:
- Combination
- Decomposition
- Displacement
- Double displacement
- Redox
b) Why is it important to indicate the physical states of reactants and products in a chemical equation? (5 marks)

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