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Molar heat capacity
Intermediate
Heat per mole per degree.
C = Q/nΔTThe heat for 1 mole per kelvin; C = Q/nΔT. For an ideal monatomic gas Cv = 3R/2 and Cp = 5R/2.
Helium at constant volume: 12.5 J/mol·K.
Differs at constant pressure and constant volume for gases.
In more detail
Molar heat capacity is the energy needed to raise one mole of a substance by one kelvin. It equals the specific heat capacity multiplied by the molar mass.
Real-world uses
- Chemists compare heat capacities of different compounds using molar values.
- Engine and reactor designs use molar heat data.
- Chemists compare the energy needed to heat different gases using molar heat capacities, which count particles rather than mass.
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Frequently asked questions
How is it related to specific heat?
Molar heat capacity equals specific heat capacity times the molar mass.
Why use moles?
Because chemical reactions occur in mole ratios, so molar values are convenient.
How is molar heat capacity different from specific heat?
Molar heat capacity uses the amount of substance in moles, while specific heat uses the mass in kilograms.
Related topics in Heat & Thermodynamics
Anomalous expansion of water · Heat · Specific heat capacity · Latent heat · Calorimetry · Phase diagrams