FullCalculator

Phase Change Energy Calculator

Custom Substance

Calculate phase change energy with custom latent heat values

Water Phase Changes

Calculate energy for water-specific phase transitions

Total Heating (with temperature change)

Calculate total energy to heat water from one temperature to another, including any phase changes

Formula

Q = mL (phase change) | Q = mcΔT (temperature change) | Water: L_f = 334 kJ/kg, L_v = 2260 kJ/kg

Frequently Asked Questions

What is latent heat?
Latent heat is the energy absorbed or released during a phase change at constant temperature. Latent heat of fusion (L_f) is for solid↔liquid transitions; latent heat of vaporization (L_v) is for liquid↔gas. For water: L_f = 334 kJ/kg, L_v = 2260 kJ/kg.
Why does temperature stay constant during a phase change?
During a phase change, all supplied energy goes into breaking or forming intermolecular bonds rather than increasing kinetic energy. Temperature only changes once the phase transition is complete. This is why boiling water stays at 100°C until all water has become steam.
What is the formula for phase change energy?
Q = mL, where Q is energy (Joules), m is mass (kg), and L is the specific latent heat (J/kg). For temperature changes within a phase: Q = mcΔT, where c is the specific heat capacity.

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