Latent Heat Calculator
Energy for phase change.
Formula first
Overview
Latent heat is the thermal energy absorbed or released by a substance during a phase change that occurs at a constant temperature. This formula quantifies the energy required to overcome intermolecular forces without changing the kinetic energy of the particles.
Symbols
Variables
Q = Heat Energy, m = Mass, L = Latent Heat
Apply it well
When To Use
When to use: Apply this equation when a substance is transitioning between solid, liquid, or gaseous states, such as melting ice or boiling water. It is used specifically during the plateau phase of a heating curve where temperature remains stationary despite heat addition.
Why it matters: This principle is foundational for engineering refrigeration cycles, steam power plants, and climate modeling. Understanding latent heat allows for the precise calculation of energy required for industrial cooling and heating processes.
Avoid these traps
Common Mistakes
- Adding Δ T in a phase change question.
- Using specific heat instead of latent heat.
One free problem
Practice Problem
A 5.0 kg block of ice at 0°C needs to be converted into liquid water at the same temperature. How much heat energy must be added if the latent heat of fusion for water is 334,000 J/kg?
Solve for:
Hint: Multiply the mass of the ice by the latent heat of fusion to find the total heat energy required.
The full worked solution stays in the interactive walkthrough.
References
Sources
- Atkins' Physical Chemistry
- Fundamentals of Heat and Mass Transfer by Incropera, DeWitt, Bergman, Lavine
- Wikipedia: Latent heat
- Halliday, Resnick, and Walker, Fundamentals of Physics
- Bird, Stewart, and Lightfoot, Transport Phenomena
- Incropera, DeWitt, Bergman, Lavine, Fundamentals of Heat and Mass Transfer
- Incropera, F. P., DeWitt, D. P., Bergman, T. L., & Lavine, A. S. (2007). Fundamentals of Heat and Mass Transfer (6th ed.).
- Atkins, P., & de Paula, J. (2014). Atkins' Physical Chemistry (10th ed.). Oxford University Press.