Question

19. What do you mean by change of state of
matter ? Explain :
(a) the change of a solid into a liquid at a
constant temperature, and
(b) the change of a liquid into a gas at a
constant temperature.​

Answer 1

Answer:

Changes of state are physical changes. They occur when matter absorbs or loses energy. Processes in which matter changes between liquid and solid states are freezing and melting. Processes in which matter changes between liquid and gaseous states are vaporization, evaporation, and condensation.

(a) The process of change of a substance from solid state into its liquid state on absorption of heat at a particular temperature is called melting/fusion and the temperature at which it happens is called the melting point.

(b). The change in state of matter of a substance from solid to liquid or from liquid to gas is brought by imparting heat energy to it while the temperature remains constant.

Explanation:

Hope this is useful for you

Answer 2

Explanation:

The change from one state to another state of matter either by absorption or rejection of heat is called Change of state of matter.

a) melting

b) vapourization