Thermochemistry Calculator
Calculate heat absorbed or released using q = mcΔT.
Select a substance from a list of specific heat capacities and enter mass and temperature change.
The fundamental equation of calorimetry relates heat, mass, specific heat capacity, and temperature change:
q = m × c × ΔT
Where q is the heat transferred (joules), m is the mass (grams), c is the specific heat capacity of the substance (J/g·°C), and ΔT = T_final − T_initial.
If ΔT is positive (temperature increased), q is positive — the substance absorbed heat (endothermic process). If ΔT is negative, q is negative — heat was released (exothermic process).
Specific heat capacities (J/g·°C):
- Water (liquid): 4.184 — the highest of common substances, which is why water is such an effective heat sink
- Ice: 2.093
- Steam: 2.010
- Ethanol: 2.44
- Aluminum: 0.897
- Iron: 0.449
- Copper: 0.385 — low specific heat means copper heats up quickly
- Gold: 0.129 — the lowest of common metals
- Concrete: 0.840
Water’s exceptionally high specific heat is why coastal climates are milder than inland ones, why oceans buffer climate change, and why water is used as a coolant in engines and nuclear reactors.
A practical application: how much energy does it take to heat 500g of water from 20°C to 100°C? q = 500 × 4.184 × 80 = 167,360 J = 167.4 kJ. That is about 0.047 kWh — roughly 0.6 cents of electricity at typical US rates.
The sign of q matters: negative q means heat flows out of the system into the surroundings. Exothermic reactions (combustion, neutralization) release heat; endothermic reactions (dissolving ammonium nitrate) absorb it.