Vaporization, Boiling & Evaporation, Types of Vaporization, Factor Affecting the Rate of Vaporization (For CBSE, ICSE, IAS, NET, NRA 2022)

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What is Vaporization?

  • Vaporization can be defined as the process in which liquid state changes into the vapour state. As a result of an increase in temperature, the kinetic energy of the molecules increases.
  • Due to the increases in kinetic energy, the force of attraction between the molecules reduces. They escape into the surrounding in the form of vapours. This process involves the consumption of heat energy.

Boiling & Evaporation

  • Liquids can also change to gases at temperatures below their boiling points. Vaporization of a liquid below its boiling point is called evaporation, When, the surface is exposed in a confined space and the liquid is in excess of that needed to saturate the space with vapor, an equilibrium is quickly reached between the number of molecules of the substance going off from the surface and those returning to it.
  • A change in temperature upsets this equilibrium; a rise in temperature, for example, increases the activity of the molecules at the surface and consequently increases the rate at which they fly off. When the temperature is maintained at the new point for a short time, a new equilibrium is soon established.
  • The pressure exerted by the vapor of a liquid in a confined space is called its vapor pressure. It differs for different substances at any given temperature, but each substance has a specific vapor pressure for each given temperature. At its boiling point the vapor pressure of a liquid is equal to atmospheric pressure.
  • For example, the vapor pressure of water, measured in terms of the height of mercury in a barometer, is at and 760 mm at (its boiling point) .

Types of Vaporization

  • Vaporization can be divided into two types.
    • Evaporation
    • Boiling
  • Evaporation is different from boiling on the basis that evaporation is a surface phenomenon, unlike boiling which is a bulk phenomenon.

Why Water is Stored in Earthen Pots?

Stored in Earthen Pots
  • The science involved in this medieval practice is evaporation. Water is stored in earthen pots especially in summers to keep the water cool. Earthen pots are made up of clay particles and have pores in them. When water is poured into the pot, it gets evaporated from the pores by absorbing heat from the remaining water in the pot.
  • This causes the cooling of the remaining water in the pot due to heat loss. Hence water is kept cool which makes it suitable for drinking during summers.

Factor Affecting the Rate of Vaporization

  • Temperature: Vaporization is directly proportional to temperature. As the temperature rises the kinetic energy of the molecules also increases. As a result, the force of attraction reduces. Hence with an increase in temperature the rate of evaporation increases.
  • Surface area: With the increase in surface area, the rate of vaporization also increases as a greater number of particles is exposed to the change in temperature.
  • Pressure: Pressure is inversely propositional to evaporation. As pressure increases, it gets difficult for the particles to gain the required kinetic energy and escape.
  • Wind speed: With an increase in wind speed, the rate also increases as particles are driven away by the wind.
The Difference between Evaporation and Vaporization

Examples of Vaporization in Our Daily Life

  • Industrially, salt is recovered from sea-water by the process of vaporization.
  • Wet clothes are dried up due to the process of vaporization.
  • The process is used in many industrial processes for separating the components of a mixture.

Questions

What is the Rate of Vaporization?

Answer:

An evaporation rate is the rate at which a material will vaporize (evaporate, change from liquid to vapor) compared to the rate of vaporization of a specific known material. This quantity is a ratio; therefore, it is unitless.

What is the Main Difference between Evaporation and Vaporization?

Answer:

  • During vaporization, all of the water can turn into gas. As for evaporation, only the top level of water is turned into gas.
  • When vaporization occurs, molecules could come from below the surface when the liquid is boiling. During evaporation, the molecules vaporize only from the surface of the liquid.

What Are the 2 Types of Vaporization?

Answer:

The Vaporization of an element or compound is a phase transition from the liquid phase to vapor. There exist two types of vaporization: evaporation and boiling.

What is Evaporation Example?

Answer:

Evaporation is defined as the process of a liquid changing into a gas. An example of evaporation is water turning into steam.

What Happens After Water Vapor is in the Air?

Answer:

  • Water is constantly cycling through the atmosphere. Water evaporates from the Earth՚s surface and rises on warm updrafts into the atmosphere.
  • It condenses into clouds, is blown by the wind, and then falls back to the Earth as rain or snow.

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