Boiling

Q.

What is the temperature of absolute zero?

Q. Why does bubbles appears when liquid is heated

Q. Evaporation takes place from:

1. Surface of liquid
2. Throughout the liquid
3. From the mid-portion of the liquid
4. Bottom of liquid

Q.

Evaporation takes place at/in _____.

1. boiling point

2. freezing point

3. between the freezing point and boiling point

4. all temperatures

Q.

Explain the factors on which evaporation depends?

Q.

Evaporation occurs at all the temperatures.

1. True

2. False

Q.

The boiling point of a liquid can be increased by ______.

1. increasing the volume of liquid

2. increasing the pressure on liquid

3. adding ice to the liquid

4. decreasing pressure on liquid

Q.

The temperature at which pressure of molecules becomes equal to the atmospheric pressure is called

1. Melting point

2. Freezing point

3. Sublimation point

4. Boiling point

Q.

Explain effect of pressure on the boiling point :-):-):-):-)

Q. Rapid conversion of water into steam is an example of ___.

1. Melting
2. Evaporation
3. Freezing
4. Vaporization

Q.

How is the heat energy supplied to a liquid used during boiling at a fixed temperature?

Q.

Boiling takes place through out the liquid.

1. Throughout the liquid
2. Surface of liquid

Q.

The rate of evaporation of a liquid increases if ___.

1. the temperature of liquid falls

2. liquid is poured into a vessel of less surface area

3. air is blown above the surface of the liquid

4. humidity increases

Q.

Boiling is a __________ process

Q.

What is the change in average Kinetic energy of molecules of a liquid during boiling at its boiling point?

Q.

Blowing air increases the rate of evaporation.

1. False

2. True

Q. Boiling takes place from:

1. Surface of liquid
2. From the mid-portion of liquid
3. None of the above
4. Throughout the liquid

Q.

Define the following term: (a) Melting point (b) Boiling point

Q. The boiling point of water can change due to different reasons. Pick the correct ones from below:

1. It decreases with increase in pressure.
2. It increases with increase in altitude.
3. It increases on the addition of impurities.
4. It decreases with an increase in altitude.

Q.

What is boiling? Explain it on the basis of the molecular motion.

Q.

It takes less time to cook vegetables in a pressure cooker

Q.

Evaporation always causes :

1. Thermal expansion

2. Liquefaction

3. Cooling down

4. All the above

Q.

What will be the effect on the pressure of water if salt is added to it?

Q.

Name two ways of changing liquid state to the vapour state and distinguish them.

Q. No heat is supplied to a liquid during evaporation. How does then the liquid change into its vapour?

Q.

Boiling results in the loss of kinetic energy of water molecules.

1. True
2. False

Q.

Why do bubbles appear when a liquid is heated?

Q.

What happens when water is heated to 100°C? How you will get the water back?

Q.

When a liquid starts to boil its temperature ___.

1. Can either increase or decrease

2. Increases

3. Remains constant

4. Decreases

Q.

Which of the following graphs shows the variation in density of water with the temperature in the range from 0 ${}^{\circ }C$ to 10 ${}^{\circ }C$?

1. 

2. 

3. 

4.