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Q = m L f (for melting/freezing), Q = m L v (for vaporization/condensation), where L f is the latent heat of fusion, and L v is the latent heat of vaporization. The latent heat of fusion is the amount of heat needed to cause a phase change between solid and liquid.
- 14.3 Phase Change and Latent Heat - College Physics 2e - OpenStax
Latent heat is measured in units of J/kg. Both L f and L v...
- 14.3 Phase Change and Latent Heat - College Physics 2e - OpenStax
The heat Q required to change the phase of a sample of mass m is given by \(\mathrm{Q=mL_f}\) (melting or freezing) and \(\mathrm{Q=mL_v}\) (evaporating or condensing), where \(\mathrm{L_f}\) and \(\mathrm{L_v}\) are the latent heat of fusion and the latent heat of vaporization, respectively.
Phase changes occur at fixed temperatures for a given substance at a given pressure, and these temperatures are called boiling and freezing (or melting) points. During phase changes, heat absorbed or released is given by \ (Q = mL,\) where \ (L\) is the latent heat coefficient.
Latent heat is measured in units of J/kg. Both L f and L v depend on the substance, particularly on the strength of its molecular forces as noted earlier. L f and L v are collectively called latent heat coefficients.
During phase changes, heat absorbed or released is given by: Q = mL where L is the latent heat coefficient.
There is no temperature change until a phase change is complete. Latent heat is measured in units of J/kg. Both[latex]\boldsymbol{L_{\textbf{f}}}[/latex]and[latex]\boldsymbol{L_{\textbf{v}}}[/latex]depend on the substance, particularly on the strength of its molecular forces as noted earlier.
If heat were added at a constant rate to a mass of ice to take it through its phase changes to liquid water and then to steam, the energies required to accomplish the phase changes (called the latent heat of fusion and latent heat of vaporization ) would lead to plateaus in the temperature vs time graph.
