Chemistry

Difference between Sublimation and Evaporation

Sublimation and evaporation are terms used to describe the phase transitions of matter. The phase of matter in the form of matter where the properties of matter are uniform throughout. The three main phases of matter are the solid phase, the liquid phase, and the gas phase. A phase transition is to convert the phase of matter from one phase to another. The main difference between sublimation and evaporation is that sublimation is the conversion of matter from a solid phase to the gas phase, while evaporation is the conversion of the liquid phase to the gas phase.

Sublimation is the transition of matter from a solid phase to a gas phase. Evaporation is the transition of matter from the liquid phase to the gas phase. This is the main difference between sublimation and evaporation.

Key differences

  • Sublimation is the conversion of matter from a solid phase to the gas phase without passing through the liquid phase, while evaporation is the conversion of the liquid phase to the gas phase.
  • In sublimation, enthalpy provides the amount of energy necessary for sublimation to occur; on the other hand, in evaporation, enthalpy gives the amount of energy that is required for evaporation to occur.
  • Sublimation occurs at pressure and temperature below the triple point of a substance; conversely, evaporation occurs at the surface of the liquid.
  • The solid phase is the initial phase for sublimation, while the liquid phase is the initial phase for evaporation.
  • Sublimation changes its phase from solid to liquid without going into a liquid state; on the other hand, evaporation changes its phase from a liquid to a gaseous state.

Difference between Sublimation and Evaporation in Tabular Form

SublimationEvaporation
DefinitionSublimation is the conversion of matter from a solid phase to a gas phase without going through the liquid phase.Evaporation is the conversion of the liquid phase into the gas phase.
IdeaOccurs at pressure and temperature below the triple point of a substanceIt occurs on the surface of the liquid.
Initial phaseThe solid phase is the initial phase.The liquid phase is the initial phase.
EnthalpyEnthalpy provides the amount of energy necessary for sublimation to occur.Enthalpy provides the amount of energy required for evaporation to occur.
Phase changeFrom solid to liquid without going into a liquid stateFrom liquid to gaseous state.

Similarities Between Sublimation and Evaporation

  • Both sublimation and evaporation produce a gas in the end.
  • Both are endothermic
  • In both processes, intermolecular forces break down to release molecules

Sublimation vs Evaporation – Overview

Sublimation is the conversion of matter from a solid phase to the gas phase without passing through the liquid phase, while evaporation is the conversion of the liquid phase to the gas phase. The solid phase is the initial phase for sublimation, while the liquid phase is the initial phase for evaporation.

In sublimation, enthalpy provides the amount of energy necessary for sublimation to occur; on the other hand, in evaporation, enthalpy gives the amount of energy that is required for evaporation to occur.

Sublimation changes its phase from solid to liquid without going into a liquid state; on the other hand, evaporation changes its phase from a liquid to a gaseous state. Sublimation occurs at pressure and temperature below the triple point of a substance; the other way.

What is sublimation?

Sublimation is the conversion of matter from a solid phase to the gas phase without going through the liquid phase. In this, the solid is transformed directly into gas. Sublimation is an endothermic reaction. Since the chemical bonds between molecules must be broken to release energy into the air, energy must be given to break the air.

This is why it is an endothermic reaction, and this energy is calculated as the enthalpy of sublimation. Sublimation occurs at pressure and temperature below the triple point of a substance.

The half liter of a substance is the pressure and temperature at which the substance exists in the three phases, that is, solid, liquid and gaseous phase.

Below the triple point, solid water is transferred, changing directly to the gas phase with an increase in temperature, and never going through the liquid state. Chemists use the sublimation technique to purify compounds. Generally, a solid is placed in a sublimation apparatus and then heated under a vacuum.

The solid condenses and volatilizes as a purified compound on a cooled surface under this reduced pressure and leaving a non-volatile residue of impurities. Once the heating is stopped and the vacuum is removed, the purified compound can be collected from the cooling surface.

Sublimation is the transition from the solid phase to the gas phase. During this phase transition, matter does not go through a liquid phase. The solid turns directly into a gas. This reaction is an endothermic reaction, as the chemical bonds between the molecules must break down to release them into the air. Since energy is released when chemical bonds are formed, energy must be given to break them. Therefore, it is endothermic. This energy is calculated as the enthalpy of sublimation.

Sublimation occurs at temperatures and pressures below the triple point of a substance. The triple point of a substance is the temperature and pressure at which the substance exists in all three phases (solid phase, liquid phase, and gas phase). Below the triple point, solid water sublimates transforms directly into a gas with an increase in temperature, and never passes through the liquid phase.

Examples of sublimation include dry ice that is converted to carbon dioxide gas at room temperature and pressure. Naphthalene is an organic compound that easily sublimates at standard temperature and pressure.

Examples

  • Water: conversion of dry ice into carbon dioxide gas at room temperature and pressure.
  • Naphthalene – An organic compound that easily sublimates at standard pressure and temperature is naphthalene.
  • Other substances: Iodine produces fumes when heated gently and liquid iodine can be obtained by controlling the temperature just above the melting point of iodine at atmospheric pressure.

What is evaporation?

Evaporation is the conversion of the liquid phase into the gas phase. Evaporation is also an endothermic process, and intermolecular forces between liquid molecules must break down to form their vapor. So this reaction requires energy to break the bonds. Therefore, it is an endothermic reaction.

Evaporation is the opposite reaction to condensation. It is directly related to temperature because when the temperature increases, so do the rate of evaporation.

Evaporation occurs on the surface of the liquid. Molecules in the middle or bottom of the liquid have a large number of intermolecular forces compared to molecules close to the surface of the liquid. Therefore,

Evaporation is the transition from the liquid phase to the gas phase. This is an endothermic process. The intermolecular forces between the molecules in the liquid must break down to form its vapor. This reaction requires energy. Therefore, it is an endothermic reaction. This is the opposite reaction of condensation.

Evaporation is directly related to temperature. When the temperature increases, the rate of evaporation also increases.

Evaporation of a liquid occurs on the surface of the liquid. Molecules near the surface of the liquid have a low amount of intermolecular forces compared to molecules in the middle or bottom of the liquid. Therefore the molecules on the surface can be released easily. These molecules are the first to become the gas phase.

There are several factors that affect the rate of evaporation. Some of these factors are given below.

  • The concentration of the substance in the air: If there is a high concentration of the substance that evaporates in the air, then the evaporation occurs slowly.
  • Air flow – higher flow increases evaporation.
  • Intermolecular forces: If the intermolecular forces are stronger, the enthalpy of evaporation is high. So evaporation is slow ..
  • Surface area: a large surface area is useful for more evaporation.

Factors that affect the evaporation rate

  • The concentration of the substance in the air: if there is a large amount of evaporating substance in the air, the evaporation process occurs gradually.
  • The air flow rate: a higher air flow rate increases evaporation.
  • Intermolecular forces: The enthalpy of evaporation is high if the intermolecular forces are stronger, then the evaporation is slow.
  • Surface area: an area with a large surface area is useful for further evaporation.

conclusion

The above discussion concludes that sublimation is the conversion of matter from a solid phase to a gas phase without entering the liquid phase, while evaporation is the conversion of the liquid phase to the gas phase. Sublimation and evaporation are terms used to name the phase transitions of matter. Although both processes describe the conversion of matter into the gas phase, the terms are different from each other. The main difference between sublimation and evaporation is that sublimation is the phase transition from solid to gas, while evaporation is the phase transition from liquid to gas.

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