Specific Latent Heat
Different substances require different amounts of energy to change them from solid to liquid and from liquid to gas. The energy required is given by the equation:
l represents the specific latent heat which is the energy required to change 1 kg of a substance from solid to liquid or liquid to gas without a change in temperature.
Specific Latent Heat is measured in Joules per kilogram, J/kg or J kg-1
The specific latent heat of fusion is the energy required to change 1 kg of solid into liquid
The specific latent heat of vaporisation is the energy required to change 1 kg of liquid into gas.
As we have just discussed, changing from a liquid to a gas takes more energy than changing a solid into a gas, so the specific latent heat of vaporisation is higher than the specific latent heat of fusion.
| Section 6 | Gas Laws | |
|---|---|---|
| Lesson 9 | ||
| Learning Outcomes | To know and be able to use the correct units for volume, temperature and pressure | |
| To be able to state Boyle’s Charles’ and the Pressure law for gases | ||
| To be able to sketch the graphs that show these laws | M.BENYOHAI |