Physical and Chemical Changes

Q. Which of the following is not a physical change?

1. Melting of ice to give water
2. Boiling of water to give water vapour
3. Dissolution of salt in water
4. Combustion of liquefied petroleum gas

Q. Classify the following as physical and chemical changes:
(i) Cleaning with soap and water
(ii) Cooking chicken
(iii) Formation of clouds
(iv) Making ice candy

1. Physical change - (i), (iii); chemical change - (ii), (iv)
2. Physical change - (i), (iii), (iv); chemical change - (ii)
3. Physical change - (i), (ii), (iii); chemical change - (iv)
4. Physical change - (i), (ii); chemical change - (iii), (iv)

Q.

Which of the following are examples of chemical reactions?

i. Burning of wood

ii. Cutting of wood

iii. Coversion of steam to water

iv. Rusting of almirah

v. Dissolving common salt in water

1. v, ii, iii

2. i, iii, v

3. ii, iv, v

4. i, iv

Q. Which of the following is an example of chemical reaction?

1. Cutting of wood
2. All of the above
3. Conversion of steam to water
4. Rusting of iron

Q.

Rusting of iron is a chemical change because

1. a new substance with new properties is produced.

2. the chemical composition of reactant is changed.

3. the change is permanent and cannot be reserved easily.

4. all of these

Q. Melting of ice is a physical change.

1. False
2. True

Q. Burning of wood is a physical change.

1. False
2. True

Q. Breaking of pencil is a physical change.

1. True
2. False

Q. Which of the following are physical changes?

1. Melting of ice
2. Burning of wood
3. Clouds formation
4. Rusting of iron
5. Melting of wax
6. Tearing of paper
7. Boiling of water
8. Cooling of water

Q. Which of the following are physical changes?

1. Melting chocolate
2. Cooking chicken
3. Formation of clouds
4. Making ice candy