Question

There are three states of matter. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily and state C has a fixed shape as well as a fixed volume.

1. Name the physical states (i) A (ii) B and (iii) C
2. Name one substance belonging to state C which can directly change into vapours on heating. What is this process known as ?
3. Name the most common substance belonging to state A that exist in nature in all three states.
4. Give examples of some substances belonging to state B.

Answer 1

Part-a)

(i) State A is liquid, according to the properties mentioned above in question. Let us have a look at the properties of liquid:

1. Liquids have a fixed volume but they have no fixed shape.
2. Liquids take the shape of the vessel in which they are placed.
3. Liquids cannot be compressed much.
4. Liquids have moderate to high densities. They are usually less dense than solids.
5. Liquids generally flow easily.

(ii) State B is gas, according to the properties mentioned above. Let us have a look at the properties of gas:

1. Gases have neither a fixed shape nor a fixed volume.
2. Gases acquire the shape and volume of the vessel in which they are kept.
3. Gases can be compressed easily.
4. Gases have very low densities.
5. Gases flow easily.

(iii) State C is solid, according to the properties mentioned above. Let us have a look at the properties of solid:

1. Solids have a fixed shape and a fixed volume.
2. Solids cannot be compressed much.
3. Solids have high densities.
4. Solids do not take the shape of the container.
5. Solids do not flow.

Part- b).

One substance belonging to state C which can directly change into vapours on heating is naphthalene balls. The process of changing a solid directly into vapour on heating is known as sublimation.

Part-c).

Water is the most common substance belonging to state A that exists in nature in all three states. Let us discuss all three states:

1. Water at room temperature or at normal conditions is in liquid state.
2. When the temperature is deceased then after freezing it converts into ice which is solid in the state.
3. When the temperature is increased by heating, water will change to its vapours or gaseous state.

Part-d).

Examples of some substances belonging to state B i.e. gaseous state are air, oxygen, nitrogen, hydrogen, helium, neon, etc.