Calorimetry Formula
Measure heat transfer in chemical processes
Formula
q = m c ΔT
- q = heat absorbed or released (J)
- m = mass (g)
- c = specific heat capacity (J·g⁻¹·°C⁻¹)
- ΔT = Tfinal - Tinitial (°C or K)
Common Specific Heats
Water: 4.184 J·g⁻¹·°C⁻¹
Aluminum: 0.897 J·g⁻¹·°C⁻¹
Copper: 0.385 J·g⁻¹·°C⁻¹
Example
Given: Heat 50.0 g water from 20°C to 80°C.
m = 50.0 g, c = 4.184 J·g⁻¹·°C⁻¹, ΔT = 80 - 20 = 60°C
q = 50.0 × 4.184 × 60 = 12,552 J ≈ 12.6 kJ
Answer: q ≈ 12.6 kJ required
Notes
- Positive q: heat absorbed (endothermic); negative q: heat released (exothermic).
- In isolated system: qhot + qcold = 0.
- Phase changes require separate calculation using ΔHfusion or ΔHvaporization.