Specific Heat Formula
Calculate heat energy needed to change an object's temperature.
Used for heating, cooling, and calorimetry.
The Formula
Q = m × c × ΔT
The specific heat formula calculates the thermal energy needed to change the temperature of a substance. Different materials require different amounts of energy to heat up — water requires much more than metal.
Variables
| Symbol | Meaning | Unit |
|---|---|---|
| Q | Heat energy transferred | Joules (J) |
| m | Mass of the substance | kg (or grams) |
| c | Specific heat capacity | J/(kg·°C) |
| ΔT | Change in temperature (T_final - T_initial) | °C or K |
Common Specific Heat Values
| Substance | c (J/kg·°C) |
|---|---|
| Water | 4,186 |
| Aluminum | 897 |
| Iron | 449 |
| Copper | 385 |
| Air | 1,005 |
Example 1
How much energy to heat 2 kg of water from 20°C to 100°C?
Q = m × c × ΔT = 2 × 4186 × (100 - 20)
= 2 × 4186 × 80
= 669,760 J ≈ 670 kJ
Example 2
A 0.5 kg aluminum pan absorbs 4,000 J. How much does its temperature rise?
ΔT = Q / (m × c) = 4000 / (0.5 × 897)
= 8.9°C
When to Use It
Use the specific heat formula when:
- Calculating energy needed to heat water, food, or materials
- Designing heating and cooling systems
- Performing calorimetry experiments in chemistry
- Estimating energy costs for industrial heating processes