Sublimation vs Evaporation
There are processes through which matter changes its form, and in normal circumstances a matter in solid state first transforms into liquefied state and then transforms into gaseous state. However, there are substances that get converted into vapor state without changing into a liquid form from their solid states. This is known as sublimation whereas evaporation is a process that applies only to liquids when they transform into a vapor state. There are similarities in the sense that both relate to matter getting converted into gaseous state but there are many differences also. This article attempts to highlight the differences between sublimation and evaporation.
What is Sublimation?
As described above, sublimation is said to have taken place when a solid substance turns into a gas without passing through a liquid state before it turns into a vapor. The best example of sublimation in everyday life is that of burning of camphor. When we bring a lighted matchstick near a piece of camphor (solid state), it catches fire and gets transformed into its vapors without entering an intermediate, liquid state. Similarly, changing of frozen carbon dioxide in it gaseous form is referred to as sublimation.
What is Evaporation?
The term vaporization mainly applies to water where it changes into water vapor with or without the application of heat. Evaporation is a process that takes place only on the surface of water without the application of heat where as vaporization that occurs with application of heat is called boiling, and not evaporation. It is the process of evaporation that makes water in an earthen pitcher become cool and drying of wet clothes in air also results because of evaporation.
Normally, in liquid state, there is intermolecular attraction that keeps molecules bonded and they are not free to leave the surface of the liquid. But molecules that are near the surface have less of this attraction and also possess enough kinetic energy to leave the surface and move out into air. However, the proportion of such molecules to the total number of molecules is very small with the result that evaporation takes place at a very small scale and at a slow rate. With some of the kinetic energy of the liquid gone through these molecules, the temperature of the liquid decreases (as in the case of an earthen pitcher and also when we feel cooler when perspiration evaporates from our bodies).
Whatis the difference between Sublimation and Evaporation?
• The change of state of matter to its gaseous phase is one similarity between evaporation and sublimation
• While in normal circumstances, solids first change into liquid state and then into vapors, there are some solids (like camphor and frozen carbon dioxide) that transform into vapors without passing through an intermediate liquid phase, that is called sublimation.
• On the other hand, evaporation refers to liquids turning into their vapors without the application of heat and mostly applies to water.