Change

Q.

Change of water into steam is a:

1. physical and chemical change

2. biological change

3. physical change

4. chemical change

Q. Making of sugar solution is which change

Q.

Fractional distillation is the separation of a mixture of miscible liquids into its component parts based on the difference in their boiling points. Based on this information, fractional distillation is a __________ process.

1. Separation of a mixture into its component parts

2. Separation of components occur due to difference in their boiling point

3. It is a special type of distillation
4. All of these

Q.

Burning of wood and rusting of the iron bar are examples of ___________ reaction.

1. physical

2. chemical

3. physical and chemical

4. biological

Q.

We observe that some portion of wax (in a candle) melts and another portion of it is used in producing heat and light.
Statement A: The melting of wax is a physical change
Statement B: The burning of wax for the production of heat and light is a chemical change.

1. Both Statement A and Statement B are false.

2. Both Statement A and Statement B are true.

3. Only Statement A is true.

4. Only Statement B is true.

Q.

Growth of finger nails is a physical change.

1. True
2. False

Q.

Changes can be helpful as well as harmful in life.

1. True

2. False

Q.

Fractional distillation is used in separation of crude oil instead of simple distillation. Why?

Q.

What do you understand by physical change and chemical change? Classify the following as physical or chemical changes:

1. Dissolving salt in water
2. Electric current is passed through water and it is broken down into oxygen and hydrogen
3. Evaporation of alcohol
4. Digestion of food

Q.

Can decolouration of the leaves in autumn be considered a change?

1. True

2. False

Q. Which observation is definite sign that a chemical change has occurred?

1. Change in temperature
2. Color change
3. Bubble formation
4. Precipitate formation
5. Salt dissolving

Q. The correct order of products in which they are extracted from crude oil in fractional distillation column from top to bottom is:

1. Natural gas, Diesel, Petrol, Paraffin
2. Natural gas, Parafin , Diesel, Petrol
3. Natural gas, Petrol, Diesel, Paraffin
4. Parafin , Natural gas, Petrol, Diesel

Q.

By giving a reason state why chemical change takes place in the following case:

Blackening of silver ware

Q. A bucket made of plastic does not rust like a bucket made of iron. Why?​

Q.

The burning of a candle is a:

1. a physical change

2. a chemical change

3. a physical and a chemical change

4. biological change

Q. Which of the following are examples of a change caused due to heating?

1. Cutting of wood
2. Drying of cloth
3. Tearing of paper
4. Writing on paper
5. Boiling of rice
6. Boiling of water
7. Cooking of food
8. Melting of ice

Q.

How is a new substance formed during a chemical change

Q.

Burning of candle is:

1. Chemical change

2. Both, physical and chemical change

3. Physical change

4. Not a change

Q.

Which of the following can be categorised as both reversible and irreversible change?

1. None of these

2. Both melting of wax and formation of curd from milk.

3. Formation of curd from milk.

4. Melting of wax in a candle.

Q. The ________ of the paper changes in the activity shown.

1. shape
2. colour
3. state
4. composition

Q. Let 'X' be a type of change that falls under the category of both physical and reversible change. Which among the following processes could 'X' be?

1. Curdling of milk
2. Burning of wood
3. Rusting of iron
4. Melting of wax

Q. (A) Liquefied petroleum gas is used in kitchens. When the gas is in a cylinder, it is in the liquid state. When it comes out of the cylinder it becomes a gas (change a), then it burns (change b). Identify the processes a and b with proper explanation.

(B) Define the following terms:
(i) Condensation
(ii) Sublimation