Energetics & electrochemistry · SL/HL
Calorimetry & Enthalpy Calculator
The default specific heat capacity is 4.18 J g⁻¹ K⁻¹ for a water-like solution. Adjust it when the model requires another value.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
q_solution = mcΔT
q_reaction = −q_solution
ΔH = q_reaction/n
| Symbol | Meaning |
|---|---|
| ΔT | T_final − T_initial; same numerical interval in °C or K. |
| n | Amount of reaction basis used for molar enthalpy. |
When to use this calculator
The sign convention here treats heat gained by the measured surroundings/solution as heat lost by the reaction. Real calorimeters may require a calorimeter constant and correction for heat loss.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- ΔT = T_f − T_i = 27.5 − (20) = 7.5 K
- q_solution = mcΔT = 100 × 4.18 × 7.5 = 3135 J = 3.135 kJ
- q_reaction = −q_solution = -3.135 kJ
- ΔH = q_reaction/n = -3.135 / 0.05 = -62.7 kJ mol⁻¹
-62.7 kJ mol⁻¹
Common mistakes
- Use the mass actually represented by the heat-capacity model.
- Keep J and kJ consistent before dividing by moles.