Change of State

Q.

Can we change solid iron into liquid? If yes, how?

Q.

______ is an example of a substance that can change its state from solid to liquid to gas.

1. Leaves

2. Ice

3. Sand

4. Petrol

Q.

Which of the following solid substances will directly convert into gas on heating?

1. Coin

2. Ice

3. Camphor

4. Wood

Q.

Name the change of state during the following changes: Formation of snow.

Q.

Name the change of state during the following changes: Melting of wax when kept in sunshine.

Q.

Iodine, camphor, and naphthalene show

1. melting

2. sublimation

3. condensation

4. freezing

Q.

Matter cannot change from one state to another.

1. True

2. False

Q.

Matter can be changed from one state to another but cannot be changed back.

1. False

2. True

Q. _______is the process in which solid changes to liquid.

1. Melting
2. Solidifying
3. Freezing
4. Boiling

Q.

The state of a substance changes from one form to another on heating or cooling. Explain.

Q.

6. When ice melts to form water, then a change occurs in its state.

1. True
2. False

Q.

Name the change of state during the following changes: Naphthalene balls become smaller when kept in air.

Q.

Water vapours change back to water on _______________

Q.

__________ is the change of solid-state directly to vapor state without going through the ________ state.

Q. Global warming has caused glaciers to melt.Identify the correct change of state of water when glaciers melt.

1. Gas -> Liquid
2. Liquid -> Gas
3. Liquid -> Solid
4. Solid -> Liquid

Q.

22. ……….is reverse of melting

Q.

Give reasons for the following statements.

The process of freezing can be easily reversed.

Q. The image below shows iron being put into moulds to make iron rods.Which of the following process helps in obtaining liquid iron from iron rods?

1. Melting
2. Cooling
3. Boiling
4. Freezing

Q. The three states of water are interchangeable due to change in ____________.

1. volume
2. wind
3. temperature
4. mass

Q. Identify the change of state observed when water is poured on dry ice.

1. Solid $\to$ Gas

2. Plasma $\to$ Liquid

3. Solid $\to$ Liquid

4. Liquid $\to$ Solid

Q.

When a liquid X is cooled at 0$°$C, it gets converted into solid state by a process called A. When the liquid is heated at 100$°$C, it gets converted into gaseous state by a process called B. Identify X, A and B.

Q.

Matter can be converted from one state to the other by _____ or _______ of heat energy.

Q.

Define the process of change from a solid to a gas.

Q.

Analyze the following statement: Camphor disappears without leaving any residue.

Q.

What are the fumes that come out when water is added to dry ice called?

1. Gaseous oxygen

2. Steam

3. Gaseous nitrogen

4. Gaseous carbon dioxide

Q. When a bowl of ice-cream is exposed to the Sun, it will .

1. freeze
2. condense
3. melt

Q.

What does dry ice give out when we spray water on it?

1. Fire

2. Fumes

3. Wet ice

4. Water

Q. Why solid carbon dioxide is known as dry ice

Q. Select the correct order of change of states of water with continuous heating.

1. Water-> Ice -> Water vapour
2. Ice -> Water vapour-> Water
3. Ice -> Water -> Water vapour
4. Water-> Water vapour -> Ice

Q.

A soild once changed into its liquid state cannot be changed back to its soild form.

1. True
2. False