Effect of Change of Temperature on State Change of Matter

Q.

What are slow and fast changes? Give examples.

Q.

If salt is dissolved in water, state its effect on Freezing point of water.

Q.

Assertion (A): A cooking gas cylinder, emptied under normal conditions, if kept in hot water, can still be used for some more time.

Reason (R): The pressure exerted by a gas is proportional to the number of collisions of gas molecules with the walls of the container.

1. Both A and R are true and R is the correct explanation of A.

2. Both A and Rare true, but R is not the correct explanation of A.

3. A is true and R is false.

4. A is false but R is true.

Q.

Some amount of common salt is dissolved in a beaker full of water. How does this affect the boiling point of water?

1. Boiling point increases.

2. Boiling point does not change.

3. Cannot be predicted.

4. Boiling point decreases.

Q.

Assertion (A): Seawater freezes below $0°\mathrm{C}$.

Reason (R): Freezing point increases due to the addition of impurities.

1. Both A and R are true and R is the correct explanation of A.

2. Both A and R are true, but R is not the correct explanation of A.

3. A is true and R is false.

4. A is false and R is true.

Q. Fire accidents in coal mines is an example of _______ combustion.

1. Rapid
2. Explosion
3. Spontaneous
4. Slow

Q.

If salt is dissolved in water, state its effect on :

Boiling point of water

Q. Meera's mom does not wash clothes on a rainy day as it takes longer to dry. This is because the rate of evaporation is to the humidity.

1. inversely proportional
2. equal
3. directly proportional

Q. Which substances can be separated by the sublimation method?

Q. (i) What do you understand by boiling?
(ii) What is the boiling point?

Q. According to the given distance of a place from seashore arrange these in increasing order of rate of evaporation of water.

1. 0 km
2. 20 km
3. 80 km
4. 200 km

Q. Which substances can be separated by the sublimation method?

Q. According to the given distance of a place from seashore arrange these in increasing order of rate of evaporation of water.

1. 0 km
2. 20 km
3. 80 km
4. 200 km

Q. Fire accidents in coal mines is an example of _______ combustion.

1. Rapid
2. Explosion
3. Spontaneous
4. Slow

Q. During boiling, the physical state of a substance changes from:

1. solid to liquid
2. liquid to solid
3. vapour to liquid
4. liquid to vapour

Q. Due to change in which of the following properties matter can change from one state to another?

1. Volume
2. Density
3. Shape
4. Temperature

Q. Due to which of the following reason clothes are preferred not to be washed on a rainy day?

1. Rate of evaporation is decreased due to increased humidity.
2. Rate of evaporation is increased due to increased humidity.
3. Rate of evaporation is decreased due to decreased humidity.
4. Rate of evaporation is increased due to increased humidity.

Q. During boiling, the physical state of a substance changes from:

1. vapour to liquid
2. solid to liquid
3. liquid to solid
4. liquid to vapour

Q. For any substance, why does the temperature remain constant during the change of state?