Vaporization

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What is Vaporization?

Vaporization can be defined as the method in which the state of the liquid transforms into the state of the vapour. The kinetic energy of the molecules increases as a result of an increase in temperature. The force of attraction between the molecules decreases as a result of the rise in kinetic energy. As a consequence, in the form of vapors, they escape into the vicinity. This approach requires heat energy.

Factors Affecting the Rate of Vaporization

  1. The concentration of an evaporating material in the air 

  2. Air Rate of Flow -

This is partly connected to the above concentration points. If 'fresh' air (i.e. air that is not already filled with a substance or other substances) is continuously flowing over the substance, the concentration of the substance in the air is less likely to increase with time, thus facilitating faster evaporation. This is the effect of decreasing the boundary layer at the evaporation surface with the velocity of flow, decreasing the distance of diffusion in the stagnant layer.

  1. The amount of minerals in the liquid that have been dissolved 

  2. Intermolecular Forces -

The greater the forces in the liquid state that hold the molecules together, the more energy one has to get to escape. This is described by the vaporization enthalpy

  1. Pressure -

When there is less effort on the surface to prevent the molecules from launching themselves, evaporation occurs faster. 

  1. Area Surface -

As there are more surface molecules per unit of volume that are theoretically able to escape, a material that has a greater surface area can evaporate quicker. 

  1. The Substance's Temperature-

The higher the temperature of the material, the greater the surface kinetic energy of the molecules, and the faster the rate of their evaporation.


Two Modes of Vaporization Exist: Evaporation and boiling. Evaporation is a surface phenomenon, while boiling is a bulk phenomenon.

Evaporation 

Evaporation is a phase transition from the liquid phase to a vapor (substance state below critical temperature) which occurs at a given pressure at temperatures below the boiling temperature. On the surface, evaporation occurs. Evaporation occurs only when a substance's partial vapor pressure is less than the equilibrium vapor pressure. For example, vapor pumped out of a solution would eventually leave behind a cryogenic liquid due to continuously decreasing pressures.

Applications

  1. Many printing and coating processes include industrial applications; recovering salts from solutions; and drying a range of materials such as lumber, paper, fabric and chemicals. 

  2. A typical preparatory step for many laboratory tests, such as spectroscopy and chromatography, is the use of evaporation to dry or concentrate samples. Rotary evaporators and centrifugal evaporators are systems used for this purpose. 

  3. Even if the ambient temperature is below the boiling point of water, when clothes are hanging on a laundry line, water evaporates. Factors such as low humidity, heat (from the sun), and wind accelerate this. 

Boiling

Boiling is  a phase change from the liquid phase to the gas phase, but boiling is the formation of vapor below the liquid surface as bubbles of vapor. Boiling takes place when the substance's equilibrium vapor pressure is greater than or equal to the ambient pressure. The boiling temperature, or boiling point, is the temperature at which boiling occurs. The boiling point varies with the environment's pressure.

Applications 

  1. Air Conditioning and Refrigeration - 

By compressing a gas so that it becomes liquid and then allowing it to boil, most forms of refrigeration and some kind of air conditioning function. This absorbs heat from the atmosphere to cool the refrigerator or freezer or to cool the air entering a house. Propane, ammonia, carbon dioxide or nitrogen are among the usual liquids. 

  1. To Make Potable Water - 

As a method of disinfecting water, it is the oldest and most efficient way to bring it to its boiling point at 100 ° C (212 ° F), because it does not affect the taste, it is effective despite pollutants or particles present in it, and is a single step process that removes most microbes responsible for causing intestinal disease.

  1. In Cooking - 

Boiling is the technique of cooking food in boiling water or other liquids such as stock or milk that are water-based.

Examples of Vaporization

  1. Industrially, salt is recovered by the vaporization process from sea-water. 

  2. The process of vaporization allows wet clothes to dry up. 

  3. The method is used for the isolation of the components of a mixture in many manufacturing processes.

Did You Know?

Sublimation is an endothermic process which occurs in its phase diagram at temperatures and pressures below the triple point of a substance, corresponding to the lowest pressure at which the substance can exist as a liquid. Deposition or sublimation, in which a substance passes directly from a gas to a solid level, is the reverse sublimation process. Sublimation has also been used as a generic term to describe a transition from solid to gas (sublimation) followed by a transition from gas to solid (deposition).


FAQ (Frequently Asked Questions)

Question: What's the difference between Vaporization and Evaporation? 

Ans: From a solid or liquid to a gas, vaporization can alter the state of matter. The liquid state of matter is directly converted into a gas during evaporation. The molecules vaporize entirely from the surface of the liquid during evaporation. 

Question: Why does Vaporization Occur? 

Ans: When a liquid material becomes a gas, evaporation occurs. It evaporates when water is heated. The molecules move and vibrate so rapidly that they escape as water vapor molecules into the atmosphere.The evaporation mechanism powers heat from the sun, or solar energy.

Question: What is required for Water to Change from Solid to Liquid or Vapor?

Ans: The amount of energy required to convert a liquid to a vapor at constant temperature and pressure is latent heat, also called vaporization heat. The energy needed to melt a solid into a liquid is called fusion heat, and the energy is the heat of sublimation.