# What are the principles of calorimetry?

Apr 17, 2014

The basic principle is the Law of Conservation of Energy: the sum of all the energies (heats) must equal zero.

1. q_1 + q_2 + q_3 + … = 0

2. Heat going into a system is positive. Heat leaving a system is negative.

The formulas for calculating the heats are:

q = mcΔT or q = ncΔT, where $c$ is the specific heat capacity and ΔT is the temperature change

q = CΔT, where $C$ is the heat capacity

q = nΔH_"rxn" or q = mΔH_"rxn"

q = mΔH_"fus" or q = nΔH_"fus"

You use $m$ for mass or $n$ for number of moles, depending on the units of the given information.

Full calculation and explanation in this video: