Effect of Pressure on State of a Substance

Q. Each of these flasks contains the same number of gas molecules. In which would the pressure be lowest?

1. Flask 1
2. Flask 3
3. Flask 4
4. Flask 2

Q. Compared to a burn due to water at ${100}^{\circ }C,$ a burn due to steam at ${100}^{\circ }C,$ is _______.

1. None of these
2. Less dangerous
3. More dangerous
4. Equally dangerous

Q. In a pressure cooker, the food is cooked faster, because the boiling point of water in the cooker ________.

1. is above ${100}^{\circ }C$
2. is below ${100}^{\circ }C$
3. is equal to ${100}^{\circ }C$
4. depends upon the amount of the volume present inside the cooker.

Q. A pressure cooker is based on the principle that boiling point of water increases with the ...........................

1. increase in pressure
   
2. decrease in pressure
   
3. both A & B
4. none of the above

Q. Can water be made to boil without heating ?

1. True
2. False

Q.

How are vapour pressure and boiling point related?

Q.

Melting point of ice-

1. Decreases with increasing pressure

2. Increases with increasing pressure

3. Is independent of pressure

4. Is proportional to pressure

Q. A bottle of water at 0${}^o$C is opened on the surface of Moon. What happens?

1. water freezes
2. water will boil
3. none of these happens
4. water decomposes into hydrogen and. oxygen

Q. Water boils at a temperature less than $100{}^{o}C$ on the top of a high mountain.

1. True
2. False

Q. Rishi is surprised when he sees water boiling at ${115}^{o}C$ in a container. Give reasons as to why water can boil at the above temperature.

Q. Select the correct alternative:
The boiling point of a liquid is increased by

1. increasing the volume of liquid
2. adding ice to the liquid
3. increasing the pressure, on liquid
4. decreasing pressure on liquid.

Q.

Comment on the following.

1. sponge though solid is compressible.
2. evaporation produces cooling of the liquid.

Q. A closed bottle containing water at ${30}^{o}C$ is carried to the moon in spaceship. If it is placed on the surface of the moon, what will happen to the water as soon as the lid is opened?

1. The water will freeze.
2. It will decompose into $H_2$ and $O_2$.
3. Nothing will happen to it.
4. The water will boil.

Q. Cooking is done fast in pressure cooker because

1. The boiling point of water is lowered
2. The boiling point of water is increased
3. More pressure is the cooker cooks the food at 100C
4. The boiling point remains the same but more steam cooks the food

Q. Water at $0^{o}C$ is taken to moon in a bottle. When bottle is opened water will:

1. Freeze
2. Remain as such
3. Boil
4. Lose temperature

Q. At atmospheric pressure, the water boils at ${100}^{\circ }C$. If pressure is reduced, it will boil at

1. Higher temperature
2. Lower temperature
3. At critical temperature
4. At the same temperature

Q.

Give an example of use of fluid pressure.

Q. Complete the following sentences:

Q. Fill in the blanks :

1. increases
2. decreases
   
3. does not change
4. can't say

Q. Boiling point of water on the celcius scale is .............

1. 0${}^o$C
2. 212${}^o$C
3. 32${}^o$C
4. 100${}^o$C

Q. Water boils at a temperature less than ${100}^o$C on the top of a high mountain.

1. True
2. False