Difference Between Sublimation and Evaporation

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 from the liquid phase to the gas phase…

Sublimation vs Evaporation

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 from 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, the enthalpy provides the amount of energy needed for sublimation to occur; on the other hand, in evaporation, the enthalpy gives the amount of energy that is required for evaporation to occur. Sublimation changes its phase from solid to liquid without entering a liquid state; on the other hand, evaporation changes its phase from liquid to gaseous state. Sublimation occurs at pressure and temperature below the triple point of a substance; the other way,

Comparison chart

Sublimation is the conversion of matter from a solid phase to the gas phase without passing through the liquid phase. In this, the solid transforms 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. That 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 pint of a substance is the pressure and temperature at which the substance exists in all three phases, i.e. solid, liquid and gas 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 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.

examples

• Water: conversion of dry ice to gaseous carbon dioxide at room temperature and pressure.
• Naphthalene: An organic compound that readily sublimes at standard temperature and pressure is naphthalene.
• Other Substances: Iodine produces fumes when gently heated, and liquid iodine can be obtained by controlling the temperature just above the melting point of iodine at atmospheric pressure.

Evaporation is the conversion of the liquid phase into the gas phase. Evaporation is also an endothermic process, and the intermolecular forces between liquid molecules must break down to form its 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, the rate of evaporation also increases. Evaporation occurs at the surface of the liquid. Molecules in the middle or bottom of the liquid have a large number of intermolecular forces compared to molecules near the surface of the liquid. Therefore,

Factors Affecting 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.
• Airflow rate: Higher airflow 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 helpful for increased evaporation.

Key differences

1. 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 from the liquid phase to the gas phase.
2. The solid phase is the initial phase for sublimation, while the liquid phase is the initial phase for evaporation.
3. In sublimation, the enthalpy provides the amount of energy needed for sublimation to occur; on the other hand, in evaporation, the enthalpy gives the amount of energy that is required for evaporation to occur.
4. Sublimation changes its phase from solid to liquid without entering a liquid state; on the other hand, evaporation changes its phase from liquid to gaseous state.
5. Sublimation occurs at pressure and temperature below the triple point of a substance; conversely, evaporation occurs at the surface of the liquid.

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 from the liquid phase to the gas phase.