Latent Heat of Phase Change
Latent Heat of Phase Change
Melting or boiling absorbs energy without any temperature rise — the latent heat. It often dwarfs the sensible heat on either side.
The latent heat is Q = m·L. where m is the mass and L the specific latent heat of the transition.
Inputs
m := 5 kg=5 kg
L_heat := 2260 kJ/kg=2.26e+06 m^2/s^2
Multiply mass by the specific latent heat.
Q := m·L_heat=1.13e+07 Nm
Results
Boiling 5 kg of water takes far more energy than heating it — latent heat is why steam carries so much energy and why sweat cools so effectively.
Assumptions & limitations
- Phase change at constant temperature/pressure.
- Pure substance.
- Latent heat constant for the transition.