- Books Name
- Science Made Easy Science Book
- Science Made Easy
- CBSE Class 9
• Latent heat
The hidden heat which breaks the force of attraction between the molecules is known as the latent heat. Since, the heat energy is hidden in the bulk of the matter, it is called latent heat.
• Latent heat of fusion
→ The heat energy required to convert 1 kilogram of a solid into liquid at atmospheric pressure,at melting point, is known as the latent heat of fusion.
→ The temperature at which a liquid starts boiling, at atmospheric pressure, is called its boiling point.
• Latent heat of vaporisation
→ The heat energy required to convert 1 kilogram of liquid into gas, at atmospheric pressure, at
boiling point, is known as the latent heat of vaporisation
→ The process, in which a gas, on cooling, turns into a liquid at a specific temperature is called
condensation or liquefaction.
Formation of clouds is due to the condensation of water vapour from the Earth’s surface.
→ The temperature at which the state of a substance changes from a liquid to a solid is called freezing point of that substance.
→ When a solid melts, its temperature remains the same because heat gets used up in changing the state by overcoming the forces of attraction between the particles. It is considered that it gets hidden into the contents of the beaker and is known as the latent heat.
→ Water vapour at 373 K have more energy than water at the same temperature because particles in steam have absorbed extra energy in the form of latent heat of vaporisation.