What is the Difference Between Evaporation and Crystallization

The key difference between evaporation and crystallization is that evaporation is the formation of vapor from a liquid, whereas crystallization is the formation of solid crystals from a liquid.

Evaporation and crystallization are physical processes that are opposite of each other. Evaporation is the physical process of conversion of a liquid into its gaseous phase at a certain high temperature. Crystallization is the physical process of the formation of crystals. It may occur as either a natural process or as an artificial process.

CONTENTS

1. Overview and Key Difference
2. What is Evaporation  
3. What is Crystallization
4. Evaporation vs Crystallization in Tabular Form
5. Summary – Evaporation vs Crystallization 

What is Evaporation?

Evaporation is the physical process of conversion of a liquid into its gaseous phase at a certain high temperature. It is usually below the boiling point of the liquid. The molecules in a liquid have different values for kinetic energy. When we provide energy from outside to the liquid (such as heat), the kinetic energy of these liquid molecules increases. When the energy is enough for the molecules on the surface to overcome the intermolecular forces between them, the molecules tend to escape the surface and convert into a gas state.

Figure 01: Evaporation

However, some of the molecules that enter the gas phase through evaporation can rejoin the liquid via condensation. This makes up an equilibrium between the evaporation rate and the condensation rate. Moreover, constant vapor pressure is established in this stage. If we increase the temperature of the liquid at this point, it leads to an increase in the rate of evaporation since the kinetic energy of the molecules increases. Therefore, the amount of molecules occupying the space above the liquid increases.

What is Crystallization?

Crystallization is the physical process of forming crystals. It may occur as either a natural process or as an artificial process. In the solid phase of a substance, the molecules or atoms are highly organized into a crystalline structure. We call this a crystal structure. A crystal can form in different ways, such as precipitation from a solution, freezing, deposition directly from a gas (rarely), etc. The heat of crystallization or enthalpy of crystallization is the energy that changes during the crystallization of a substance.

Figure 02: Crystallization of Sodium Acetate

There are two major steps of crystallization: nucleation (a crystalline phase appears either in a supercooled liquid or a supersaturated solvent) and crystal growth or particle growth (the increase in the size of particles and leads to a crystal state).

What is the Difference Between Evaporation and Crystallization?

Evaporation and crystallization are physical processes that are opposite to each other. The key difference between evaporation and crystallization is that evaporation is the formation of vapor from a liquid, whereas crystallization is the formation of solid crystals from a liquid. Moreover, evaporation can remove a more volatile substance from a liquid mixture, whereas crystallization can remove a solid from a liquid.

The below infographic lists the differences between evaporation and crystallization in tabular form for side by side comparison.

Summary – Evaporation vs Crystallization

Evaporation and crystallization are physical processes that are opposite to each other. Evaporation is the conversion of a liquid into its gaseous phase at a certain high temperature. Crystallization is the formation of crystals and may occur as either a natural process or as an artificial process. The key difference between evaporation and crystallization is that evaporation is the formation of vapor from a liquid, whereas crystallization is the formation of solid crystals from a liquid.