Dear Student
Gas or vapour converts into a liquid when condensation takes place.
Temperature is the major factor responsible for the changes in the three states of matter, in short increase or decrease in the temperature brings about the changes in the three states of matter.
To change the state from a gas to liquid, there is a need for removal of energy.
The total amount of heat required to change a unit mass of liquid into a gas (or vapour state), without any change in the temperature is known as the Latent Heat of Vapourisation.
For water, Latent Heat of Vapourisation is 2,260 kJ/Kg, according to which 1 kg of water requires a heat of 2,2,60 kJ for converting into 1 kg of vapour at a temperature of 373 K.
Now, 2,260 kJ of heat will be released when 1 kg of water is condensed at a temperature of 373 K in order to convert into 1 kg of water at the same temperature.
If we cool this gas beyond this boiling point, then it get transformed (or changed) into a liquid, which is known as condensation. Therefore, when a liquid is cooled beyond its freezing point, it is known as freezing. The freezing point of water is 273 K and the boiling point of water is 373 K.
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