How it’s calculated
The heat needed to change a material’s temperature is proportional to its mass, its specific heat capacity and the temperature change. A temperature change of 1 °C equals a change of 1 K.
Example (OpenStax Chemistry 2e §5.1): heating 800 g of water (c = 4.184 J/g·°C) from 21 °C to 85 °C takes q = 800 × 4.184 × 64 = 214,221 J ≈ 214 kJ.
In the same section a 348 g metal absorbs 6.64 kJ and warms from 22.4 °C to 43.6 °C, so c = 6,640 ÷ (348 × 21.2) = 0.900 J/g·°C, consistent with aluminum.
Frequently asked questions
What is the specific heat of water?
4.184 J/(g·°C), which is one calorie per gram per degree. It is unusually high, which is why water warms and cools slowly.
Does this include melting or boiling?
No. q = mcΔT applies only within one phase. Melting or boiling absorbs latent heat at constant temperature, which must be added separately.
Why is the heat negative?
A negative q means heat leaves the material: it cools down.
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Sources
- Chemistry 2e, §5.1 Energy Basics — OpenStax
- College Physics 2e, §14.2 Temperature Change and Heat Capacity — OpenStax
Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.
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