Vaporization and Evaporation

[박진호]

Vaporization vs Evaporation

Vaporization is a transitional phase of an element or compound from a solid phase or liquid phase to a gas phase. It can also refer to the physical destruction of an object due to intense heat. It is the process of applying heat to change something from a solid or liquid to a gas. It changes matter from one state or phase into another without changing its chemical composition.

Vaporization has three types:

Boiling, wherein the transition from liquid phase to gas phase takes place at or above the boiling temperature, and it occurs below the surface.

Sublimation, wherein the transition from solid phase to gas phase takes place without passing through a liquid phase, and it occurs at temperatures and pressures below the triple point of a substance.

Evaporation, wherein the transition from liquid phase to gas phase takes place below the boiling temperature at a given pressure, and it occurs on the surface.

Evaporation, therefore, is a type of vaporization of a liquid into gas on its surface. It is a part of the water cycle wherein solar energy causes the evaporation of water from oceans, seas, and other bodies of water as well as the moisture in the soil. When water is exposed to air, liquid molecules turn into vapor and rise up to form clouds where they are accumulated until such time that they are released back to earth as rain.

Liquid molecules must be located near the surface, move in the right direction, and have enough kinetic energy for them to evaporate. Since only a small amount of molecules have these factors, the rate of evaporation is constrained.

Heat, humidity, and air movement are key factors that can affect the rate of evaporation. Higher temperatures cause faster evaporation, and laundry will dry more quickly on the clothesline if it is windy. Low humidity also causes liquid to evaporate quicker.

The following forces also play important roles in the process of evaporation:

Pressure. If there is less exertion on the surface, evaporation happens faster.

Surface Area. Substances with large surfaces evaporate faster because more surface molecules are able to escape.

Temperature. The higher the temperature and the average kinetic energy of the molecules, the faster the evaporation.

Density. Liquid evaporates slowly with higher density.

A substance will likewise evaporate slowly if the air already has a high concentration of the said substance or if there are other substances in the air.

Summary:

1.Vaporization is a transitional phase of an element or compound from a solid phase or liquid phase to a gas phase while evaporation is a type of vaporization wherein the transition from a liquid phase to a gas phase takes place below the boiling temperature at a given pressure, and it occurs on the surface.

2.Vaporization changes the phase or state of matter from a solid or liquid to a gas while evaporation changes the liquid state of matter into a gas.

3.Vaporization can occur with boiling, sublimation, or evaporation while evaporation can happen with the right amount of heat, humidity, and air movement.

※ triple point

- 3중점(重點) ((기상(氣相)·액상(液相)·고상(固相)의 평형점))

- the temperature and pressure at which the three phases of a substance are in equilibrium. The triple point of water, 273.16 K at a pressure of 611.2 Pa, is the basis of the definition of the kelvin