Chemical Reactions and Equations

Grade 9 Science — Chemical Reactions and Equations: 25 practice questions with instant scoring and explanations.

1. Which of the following is an example of a combination reaction?
2. What type of reaction is: CaCO₃ → CaO + CO₂?
3. In the reaction Zn + CuSO₄ → ZnSO₄ + Cu, what type of reaction occurs?
4. Which reaction is an example of double displacement?
5. An endothermic reaction is one that:
6. Which of the following is an exothermic reaction?
7. The chemical equation 2H₂ + O₂ → 2H₂O is balanced. What does the '2' in front of H₂O represent?
8. In a balanced chemical equation, what must be equal on both sides?
9. Which statement correctly describes oxidation in terms of oxygen?
10. In the reaction 2Mg + O₂ → 2MgO, magnesium is:
11. When a candle burns, is the reaction exothermic or endothermic?
12. Which of the following represents a neutralisation reaction?
13. A reaction in which two reactants combine to form a single product is called a:
14. In the decomposition of potassium chlorate (KClO₃), the products are:
15. Which reaction demonstrates both oxidation and reduction (redox)?
16. When iron is heated in oxygen, the product formed is:
17. What does the symbol (↓) represent in a chemical equation?
18. The reaction: H₂ + Cl₂ → 2HCl is classified as a:
19. In an exothermic reaction, which of the following is true?
20. When copper reacts with dilute nitric acid, the gas produced is:
21. What type of reaction occurs when a more reactive metal displaces a less reactive metal from its salt?
22. In the reaction 2AgNO₃ + Mg → Mg(NO₃)₂ + 2Ag, the reducing agent is:
23. Which is an example of a thermal decomposition reaction?
24. When a substance burns in oxygen with a flame and heat, the reaction is called:
25. The reaction AgNO₃ + NaCl → AgCl↓ + NaNO₃ can be classified as: