Physical and Chemical Changes

Grade 7 Science — Physical and Chemical Changes: 25 practice questions with instant scoring and explanations.

1. A physical change is one in which
2. A chemical change results in the formation of
3. Which of the following is a physical change?
4. Which of the following is a chemical change?
5. Rusting of iron is a
6. Rusting occurs when iron reacts with
7. The process of coating iron with a layer of zinc to prevent rusting is called
8. A reversible change is one that can be
9. Which of the following is a reversible change?
10. An irreversible change is one that
11. Crystallization is the process of
12. When salt solution is evaporated, salt crystals are formed. This is an example of
13. Sublimation is the direct conversion of
14. Which of the following undergoes sublimation?
15. When sugar is heated strongly, it turns black due to
16. In the process of galvanization, the metal layer applied is
17. Which of the following can be reversed by cooling?
18. When iron filings are heated with sulfur, a new black compound is formed. This is a
19. Photographic paper darkens when exposed to light. This is a
20. The breaking down of a substance into simpler substances is called
21. Heat is required for which of the following to occur?
22. Which change produces new substances?
23. Rusting of iron can be prevented by
24. The boiling of water is a
25. When a matchstick is lit, the burn mark on the ground is due to