A melted chocolate is kept in a refrigerator. It solidifies again. This is an irreversible change. (2024)

Q. Melting of a candy bar is an irreversible change.

Q. M kilograms of a material are to be kept in melted state at melting point and power required for this purpose is P. When power source is disconnected then the sample completely solidifies in t sec. The latent heat of fusion of the material will be :

Q. Fill in the blanks with the correct words.
1. Melting of ice-cream is an example of a/an .................... (reversible/irreversible) change.
2. Ripening of fruits is an example of a/an .................... (reversible/irreversible) change.
3. Cooking of foood is an example of a/an .................... (reversible/irreversible) change.
4. Breaking of glass is a .................... (physical/chemical) change.
5. .................... (Heating/Cooling) causes steam to change into water.

Q. Write True (T) or False (F) against the following statements in the given brackets:
1. Digestion of food is a Q irreversible change. ( )
2. Rusting of iron is a reversible change. ( )
3. Melting of wax is a reversible change. ( )
4. Curding of milk is an irreversible change. ( )
5. Melting of ice cream is a reversible change. ( )