Question

Explain how camphor disappears without leaving any residue.

Answer 1

Hint: Approach this question by recalling the concept of sublimation. As we know that sublimation is defined as the changing of a substance directly from solid to the gaseous state, without passing through the liquid state. So here we have to explain the disappearance of camphor without leaving any residue.

Complete answer:
Let us understand about sublimation process as follows:-
Sublimation: it is an endothermic process and occurs at a certain temperature and pressure that is lower than the substance’s triple point in its phase diagram. This pressure condition is the lowest pressure where substance can exist as a liquid.
-The reverse of sublimation is called deposition, in which a substance passes from gaseous phase to solid phase.
-In case of evaporation, the transition occurs from liquid to gas if it takes at a temperature lower than the boiling point of the liquid and also the process of boiling occurs at only boiling point. When there is no such distinction in solid to gaseous transition, then it is definitely a sublimation process.
-Camphor does disappear after some time as its surface gains kinetic energy and it directly gets converted into gaseous state.
-Therefore we can say that when camphor is provided with the right amount of heat, it gets converted into gas and disappears without leaving any residue.

Note:
-Remember that sublimation process requires a specific amount of energy to take place and this energy is known as sublimation energy.
-The best example of sublimation is dry ice (that is a solid form of carbon dioxide), which when converted into a gaseous state, looks like a fog.