Changes around us Worksheet-9

Changes around us Worksheet-9

True/False:

1. Contraction in gases is much more as compared to solids.
2. Filling air in a bicycle is a reversible change.
3. The effect of cooling is opposite to that of heating.
4. Burning of paper is an irreversible change.
5. Blowing air into a balloon is a reversible change.
6. Frying a fish is a chemical change.
7. If we hold a lid over the container, the steam will liquefy or condense into small droplets of water on coming in contact with the hot lid.
8. The three physical states of water are reversible and can be changed by heating or cooling.
9. An unripe mango is yellow and sweet, but on ripening it usually becomes green and sour.
10. Curdling of milk is done by adding lemon juice to curd for making cottage cheese or paneer.
11. Burning of a candle wax releases carbon monoxide and water vapour.
12. Gases expand the most while solids expand the least.
13. James Prescott Joule studied the nature of heat, and discovered its relationship to mechanical work.
14. Huge gaps, called expansion gaps, are deliberately left between the rails as there is an expansion of the rails in hot weather.
15. The jammed metal lid of a jam jar can be opened by heating.
16. The effect of cooling is opposite to that of heating.
17. Expansion in gases is much more as compared to solids.
18. Melting of butter and chocolate is irreversible.
19. Freezing of water is a chemical change.
20. Burning of paper is a reversible change.

Answer Key:

1. True
2. True
3. True
4. True
5. True
6. True
7. False
8. True
9. False
10. False
11. False
12. True
13. True
14. False
15. True
16. True
17. True
18. False
19. False
20. False