Calorimetry Calculator (Heat and Enthalpy of Reaction)
Enter the solution mass, specific heat and temperature change to get q and ΔH.
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Calorimetry Calculator (Heat and Enthalpy of Reaction) by TheCalcTools
How the Calorimetry Calculator (Heat and Enthalpy of Reaction) works
In a coffee-cup calorimeter, heat released by the reaction warms the solution: q = m c ΔT. The reaction’s enthalpy change is the negative of that heat, divided by the moles that reacted.
Dilute aqueous solutions are usually assumed to have the specific heat and density of water (4.184 J/(g·°C), 1 g/mL).
The formula
Worked example
Using the default values shown in the calculator:
| Mass of solution (g) | 100 |
|---|---|
| Specific heat (J/(g·°C)) | 4.184 |
| Initial temperature (°C) | 21 |
| Final temperature (°C) | 27.5 |
| Moles of limiting reactant | 0.05 |
- q = 100 × 4.184 × 6.5 = 2,719.6 J.
- ΔH = −2,719.6 J ÷ 0.05 mol = -54.39 kJ/mol.
Result:
| Heat gained by the solution q (J) | 2,719.6 |
|---|---|
| Enthalpy change of reaction ΔH (kJ/mol) | -54.39 |
| Reaction type | Exothermic (releases heat) |
Frequently asked questions
Why is ΔH negative when the temperature rises?
The solution gained heat because the reaction released it, so the reaction’s enthalpy decreased: an exothermic reaction.
Sources and further reading
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