Calorimetry measures heat flow. In a simple coffee-cup calorimeter, a reaction warms or cools water, and the temperature change tells you the heat. Food Calories were first measured this way.
How to use the Calorimetry Calculator
- Method
- Mass m
- Substance
- Specific heat c
- Initial temperature
- Final temperature
- Molar mass M (g/mol)
- Molar enthalpy ΔH (kJ/mol)
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose the method. For the calorimeter, choose the substance (water by default) and enter the mass and initial and final temperatures.
Tips
- Use absolute temperature (K) in gas laws and efficiency formulas.
- Temperature differences are the same in K and °C.
- Heat = mass × specific heat × temperature change when no phase change occurs.
- Phase changes need latent heat at a constant temperature.
Common mistakes to avoid
- Using °C in pV = nRT.
- Forgetting latent heat during melting or boiling.
- Confusing heat capacity (J/K) with specific heat (J/(kg·K)).
Inputs explained
| Field | What to enter |
|---|---|
| Method | Choose one: Temperature change (q = mcΔT), Molar enthalpy (q = nΔH) |
| Mass m | Units: g, kg, mg, lb, oz, gr |
| Substance | Choose one: Water, Ice, Steam, Air … |
| Specific heat c | Units: J/(kg·K), kJ/(kg·K), J/(g·K), BTU/(lb·°F), cal/(g·°C) |
| Initial temperature | Units: °C, °F, K |
| Final temperature | Units: °C, °F, K |
| Molar mass M (g/mol) | A number |
| Molar enthalpy ΔH (kJ/mol) | A number |
Example values
How the main result changes when Mass m changes and everything else stays at the example values above:
| Mass m (g) | Heat q (J) |
|---|---|
| 50 | 1,359.15 |
| 75 | 2,038.725 |
| 100 | 2,718.3 |
| 125 | 3,397.875 |
| 150 | 4,077.45 |
| 200 | 5,436.6 |
Formula
q = m·c·ΔT · q = (m/M)·ΔHWorked example
Inputs — Method: Temperature change (q = mcΔT); Mass m: 100 g; Substance: Water; Initial temperature: 20 °C; Final temperature: 26.5 °C.
Results — Heat q = 2,718.3 J; Process = Heat absorbed by the substance.
Key terms
- Specific heat
- Heat needed to warm 1 kg by 1 K.
Frequently asked questions
What is a coffee-cup calorimeter?
An insulated cup at constant pressure, measuring enthalpy changes.
Why use water?
It has a high, well-known specific heat.
What sign does an exothermic reaction have?
The reaction's q is negative; the water's is positive.
What about the calorimeter itself?
Precise work adds its heat capacity.
What formula does the Calorimetry Calculator use?
q = m·c·ΔT · q = (m/M)·ΔH.