Calorimetry is used to find the amount of heat released or absorbed during a reaction. A simple method relies on using the heat to warm up a known mass of water by a known amount.
Specific heat capacity is the energy required to raise the temperature of 1 g of a substance by 1 °C.
The equation below is used to work out how much heat is absorbed by the water:
q = m × c × ΔT where q = heat energy, J
m = mass of water, g
c = 4.2 J g–1 K–1
ΔT = change in temperature, K
Note that 100 cm3 of water has a mass of 100 g, c is the specific heat capacity of water, and a change in temperature by 1 °C is also a change by 1 K.
A bomb calorimeter can be used to accurately measure heats of combustion.
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