Question

What are the principles of calorimetry?

Answer 1

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: