Question

do all substances change from solid to liquid and liquid to gas on heating ?explain ?​

Answer 1

ANSWER :

FACT :

When we heat ice , it changes to water and if heat that water , it changes to gas.

If we cool the gas , it changes to water and if we cool the water , it changes to ice.

But in some cases , solid directly changes into gas and gas directly changes to solid.

1. Solid to gas : Sublimation

Some substances like naphthalene balls , when we keep them outside for sometime , they change into gas.

The direct change of state from solid to gas is called sublimation.

Examples :

Dry ice(solid form of $co_{2}$), iodine crystals and ammonium chloride etc.

2 . Gas to solid : Deposition

Direct change of state from gas to solid is called Deposition.

Example:

Vapour of ammonium chloride and vapour of iodine crystals , carbondioxide can be changed into dry ice.

CONCLUSION :

Therefore, some substances change directly from solid to gas and gas to solid.

Answer 2

Answer:

1. No,All substances do not change from solid to liquid and from liquid to gas.
2. Substances such as camphor and ammonium chloride change from solid to gaseous state of on heating.
3. Solid camphor on heating changes to directly from solid state to gaseous state and vice versa without passing through liquid state.
4. This phenomenon is called "sublimation".