Physical and chemical changes Quiz - ICSE Class 7 Science

Free practice quiz: Physical and chemical changes (ICSE Class 7 Science). 46 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 7 Science practice quiz has 46 multiple-choice questions on Physical and chemical changes, and 46 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following is an example of a reversible physical change?

   1. Burning of wood
   2. Rusting of iron
   3. Melting of ice
   4. Digesting food
   Show answer

   Answer: C. Melting of ice

   Melting of ice is a physical change because only the state of matter changes (solid to liquid), and it can be reversed by freezing. Burning wood, rusting iron, and digesting food are chemical changes as new substances are formed and they are generally irreversible.

2. Which of the following is a characteristic of a chemical reaction often observed as a sign of a chemical change?

   1. Change in size
   2. Change in shape
   3. Formation of gas bubbles
   4. Change in state without heat
   Show answer

   Answer: C. Formation of gas bubbles

   Formation of gas bubbles (effervescence) is a common indicator that a new substance (a gas) is being formed, which is characteristic of a chemical change. Changes in size, shape, and state are usually physical changes.

3. Which of the following is NOT a reversible physical change?

   1. Stretching a rubber band
   2. Condensation of steam
   3. Burning a log of wood
   4. Dissolving sugar in water
   Show answer

   Answer: C. Burning a log of wood

   Burning a log of wood is a chemical change that converts wood into ash, carbon dioxide, and water vapor, which cannot be easily reversed. Stretching a rubber band, condensation of steam, and dissolving sugar are physical changes that are generally reversible.

4. The process of breaking a stone into smaller pieces is:

   1. A chemical change because its size changes
   2. A physical change because its chemical composition is unaltered
   3. A chemical change because it is irreversible
   4. A physical change because it is reversible
   Show answer

   Answer: B. A physical change because its chemical composition is unaltered

   Breaking a stone changes its size and shape but not the chemical makeup of the stone. Therefore, it's a physical change. While reassembling the stone might be impractical, the nature of the change is physical.

5. The process of respiration in living organisms is:

   1. A physical change
   2. A reversible physical change
   3. An irreversible chemical change
   4. A temporary physical change
   Show answer

   Answer: C. An irreversible chemical change

   Respiration is a complex series of metabolic chemical reactions that break down glucose in the presence of oxygen to release energy, carbon dioxide, and water. This is a chemical change and is irreversible in the context of the biological process.

More questions in this quiz

Answers and explanations are in the full quiz.

1. When iron reacts with oxygen in the presence of moisture, it forms rust. This is an example of:
2. The process of evaporation of water into water vapor and condensation of water vapor back into water is a demonstration of:
3. Which of the following changes involves the formation of a new substance with different properties?
4. A change where the form or appearance of a substance changes, but its chemical identity remains the same, is called:
5. Which of these is NOT a characteristic of a chemical change?
6. When sugar is heated strongly, it turns into a black mass. This is an example of:
7. Dissolving salt in water is a physical change because:
8. The process of photosynthesis in plants is an example of:
9. Which of the following changes would result in a change of smell?
10. When iron filings are mixed with sulfur powder, a greyish-black mixture is formed. If this mixture is heated, a hard, black substance called iron sulfide is formed. The formation of iron sulfide is:
11. The change in which a substance undergoes a change in its state of matter but not in its chemical composition is called:
12. Which of the following is a physical change?
13. The burning of coal is an example of:
14. Which of the following changes results in the absorption of heat energy?
15. The process of making pickles involves chemical changes that preserve the vegetables. This is primarily due to:
16. When iron nails are left in a damp environment, they turn reddish-brown. This process is best described as:
17. The process of sublimation, where a solid directly turns into a gas without becoming a liquid, like dry ice (solid carbon dioxide), is an example of:
18. When water boils and turns into steam, this is:
19. The change of milk into curd is:
20. Which of the following indicates that a chemical change has occurred?
21. When magnesium ribbon burns in air, it produces a white ash. This is:
22. The rusting of iron is a process where iron reacts with oxygen and water. This is an example of:
23. When a substance changes from solid to liquid and then to gas upon heating, these are called:
24. Which of the following is a characteristic of physical changes?
25. When sodium reacts with chlorine, sodium chloride (common salt) is formed. This is:
26. Which of the following involves the release of heat energy?
27. The process of digestion of food in our body is:
28. When a substance changes color during a process, it is often an indication of:
29. Consider the formation of carbon dioxide from carbon and oxygen. This is:
30. The process of freezing water into ice is:
31. Which of the following is an example of a change that cannot be easily reversed?
32. When baking soda is mixed with vinegar, effervescence (bubbles of gas) is observed. This indicates:
33. Which of these processes is primarily a physical change?
34. When iron is heated in the absence of air, it does not rust. Rusting requires:
35. Which of the following is an endothermic process (absorbs heat)?
36. The process of making salt from saltwater by evaporation is:
37. When a metal rod is heated, it expands. This is:
38. Which of the following involves the formation of a precipitate?
39. The transformation of wood into ash and smoke when burned is a clear example of:
40. Which of the following is a process that absorbs energy from the surroundings?
41. The process of crystallisation of salt from its solution is:

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