Specific Latent Heat¶
The specific latent heat of a substance, is the amount of energy per kilogram required to change the state of said substance.
-
The latent heat of fusion is the energy required for the state change: solid -> liquid (melting).
-
The latent heat of vaporisation is the energy required for the state change: liquid -> gas (evaporation).
Equation¶
This equation will be on the Physics equation sheet!
\[
E = mL
\]
Where:
- \(E\) is the energy for a state change, in Joules (J)
- \(m\) is the mass, in kilograms (kg)
- \(L\) is the specific latent heat, in Joules per kilogram (J/kg)
Example¶
For example, lets say I had 2.4kg of ice, and I wanted to melt it to liquid water. The latent heat of fusion for water is \(33400 J/kg\), I want to know how much energy that will require.
\[
\begin{align}
E & = m * L \\
& = 2.4 * 33400 \\
& = 80160J \\
& = 80.16kJ
\end{align}
\]
Therefor I would need to use \(80.16 kJ\) of energy to make the ice melt.
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