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Thermochemistry & Thermodynamics

Molar Heat Capacity

The heat required to raise the temperature of one mole of a substance by one kelvin.

Formula / equation C_m = q / (nΔT)
Unit J/(mol·K)

In depth

Expressing heat capacity per mole compares substances particle for particle rather than gram for gram. For monatomic gases the value is close to the theoretical (3/2)R at constant volume, while for solid elements it approaches 25 J/(mol·K) — the empirical Dulong–Petit law.

Examples in the real world

Helium is 12.5 J/(mol·K) at constant volume; most metallic solids cluster near 25 J/(mol·K) at room temperature.