Specific Latent Heat — Ice & Water

Phase change · Q = mL · L = 334 000 J/kg (latent heat of fusion) · Hydrogen bonds · Temperature stays constant at 0°C

Temp (°C) Energy added → 0 +20 −20 ICE Q = mL latent heat · T constant WATER Q=mcΔT Q=mcΔT L = 334 000 J/kg (latent heat of fusion)
Ice — Rigid Lattice
Water molecules locked in a rigid crystal lattice by hydrogen bonds (dashed lines). Molecules only vibrate — no movement. Adding heat at 0°C breaks the bonds without raising temperature.
AQA: Specific latent heat of fusion: Q = mL, where L = 334,000 J/kg for water (ice→water). This energy breaks hydrogen bonds without raising temperature. Compare: warming 1 kg of ice by 1°C needs only 2,100 J; melting the same mass needs 334,000 J. Toggle Melting to see bond-breaking.
H₂O · 4 hydrogen bonds per molecule · rigid ice lattice
Q = mL · L = 334 000 J/kg · bonds breaking
T = 0°C · temperature stays CONSTANT
ICE · Rigid Hydrogen-Bond Lattice
Hover molecules · Drag to orbit · Scroll to zoom · Dbl-click to reset
Temperature
−20°C → 0°C
■ T = CONSTANT
Equation
Q = mcΔT
c = 2 100 J/kg°C
Energy → vibration (kinetic energy ↑)
H-bonds: 24 / 24
Polarity
O (red)   = δ− (negative)
H (cream) = δ+ (positive)
δ+···δ− = H-bond