Heat Capacity
Calculate heat capacity, heat transfer, and calorimetry results using specific heat capacity (q = mcΔT), molar heat capacity (q = CΔT), Cp/Cv ratios, and calorimetry principles.
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For educational and informational purposes only. Verify with a qualified professional.
📋 Key Takeaways
- • q = mcΔT | Specific heat: heat per gram per degree
- • q = nCΔT | Molar heat: heat per mole per degree
- • Cp - Cv = R | For ideal gases (R = 8.314 J/(mol·K))
- • qlost = qgained | Calorimetry principle
Did You Know?
Water has the highest specific heat of common liquids (4.184 J/(g·K)), moderating Earth's climate.
Source: NIST
Dulong-Petit law: molar heat capacity of solids ≈ 3R ≈ 25 J/(mol·K) at high T.
Source: IUPAC
Monatomic gases: Cv = 3R/2, Cp = 5R/2; diatomic: Cv = 5R/2, Cp = 7R/2.
Source: Kinetic theory
Heat capacity varies with temperature; values are often given at 25°C.
Source: CRC Handbook
Bomb calorimeters measure heat at constant volume (ΔU); coffee cups at constant P (ΔH).
Source: Thermochemistry
The Cp/Cv ratio (γ) is 1.67 for monatomic, 1.40 for diatomic ideal gases.
Source: Thermodynamics
How the Heat Capacity Calculator Works
Enter mass/moles, specific or molar heat capacity, and temperature change to compute heat transfer. For calorimetry, enter water and substance masses and temperatures to find unknown heat capacity.
Specific Heat
q = mcΔT — mass × specific heat × ΔT
Molar Heat
q = nCΔT — moles × molar heat capacity × ΔT
Expert Tips
Use Kelvin
ΔT is the same in K or °C; use K for consistency.
Substance Database
Select from 30+ substances for instant c, Cp, Cv values.
Calorimetry
Ensure hot object is fully immersed; stir for equilibrium.
Sign Conventions
Heat in = positive; heat out = negative.
Specific Heat Comparison (J/(g·K) at 25°C)
| Substance | Specific Heat | Category |
|---|---|---|
| Water | 4.184 | Liquid |
| Copper | 0.385 | Metal |
| Aluminum | 0.897 | Metal |
| Iron | 0.449 | Metal |
| Ethanol | 2.44 | Liquid |
| Hydrogen (gas) | 14.3 | Gas |
Frequently Asked Questions
What is specific heat capacity?
The heat required to raise 1 g of a substance by 1 K. Water = 4.184 J/(g·K).
What is molar heat capacity?
Heat per mole per degree. C = c × M where M is molar mass.
Why does water have high heat capacity?
Hydrogen bonding stores energy in molecular motion; water moderates climate.
What is Cp vs Cv?
Cp = constant pressure (most processes); Cv = constant volume (bomb calorimeter). Cp - Cv = R for ideal gases.
How does calorimetry work?
Heat lost by hot object = heat gained by water + calorimeter. Solve for unknown c.
When is heat capacity temperature-dependent?
Always, but often assumed constant near 25°C for engineering estimates.
What units for heat?
Joules (J) or kilojoules (kJ). 1 cal = 4.184 J.
Key Numbers
📚 Official Sources
⚠️ Disclaimer: This calculator uses thermodynamic equations and published data. For precise work, consult NIST Chemistry WebBook for heat capacity data, IUPAC Gold Book for definitions, and CRC Handbook for thermodynamic tables.
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