[[Phase change]]
# Heat of transformation
The heat of transformation is the [[Heat]] required to complete a phase change.
It is given by
The heat of transformation is given by
$$
\begin{align*}
Q = mL
\end{align*}
$$
where $L$ is the **latent heat** for the phase change.
Specifically,

- $L_f:$ Latent heat of fusion for the material at that temperature and pressure.
- $L_v$: Latent heat of vaporisation for the material at that temperature and pressure.

The sign, depending on the direction of phase change, is usually added by hand.
It is usually assumed that a substance is in a set of standard conditions
(temperature and pressure)
for the $L$ value.

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#state/tidy | #SemBr