Latent heat

The latent heat from phase

α

to phase

β

is

L = T (S_{β} - S_{α}) = H_{β} - H_{α}

per mole or per particle, according to the normalization used.

Table of contents
- Stefan number Latent heat
  - Latent-to-sensible heat ratio Stefan number
- Clausius-Clapeyron relation Latent heat

Stefan number ( $Ste = c_{p} Δ T / L$ )

The Stefan number compares sensible heat

c_{p} Δ T

with latent heat

L

per unit mass. Some solidification literature uses its reciprocal as the Stefan parameter, so the defining formula must accompany the convention.

Latent-to-sensible heat ratio ( $S = L / (c_{p} Δ T)$ )

The latent-to-sensible heat ratio is the reciprocal of the Stefan number defined by

Ste = c_{p} Δ T / L

. Large

S

means that phase change uses much more energy than changing temperature by

Δ T

.

Clausius-Clapeyron relation

Along a first-order coexistence curve,

\frac{d p}{d T} = \frac{S _{β} - S _{α}}{V _{β} - V _{α}} = \frac{L}{T ( V _{β} - V _{α} )} .

At a critical point the two phases merge, their entropy jump vanishes, and the latent heat tends to zero.

 Ancestors (7)

 Incoming links (44)

 View article source

 Discussion (0)

There are no discussions about this article yet.

 Articles by others on the same topic (1)

Wikipedia Bot  1

Latent heat is the amount of energy required to change the state of a substance without changing its temperature. This energy is absorbed or released during phase transitions, such as melting (solid to liquid), freezing (liquid to solid), boiling (liquid to gas), or condensation (gas to liquid).

 Read the full article

  See all articles in the same topic Create my own version