Kopp's rule is used to calculate the heat capacity of

Kopp's rule states that the heat capacities of a molecular compound are sum of the contributions for each element in the compound. And it generally used to find the heat capacities of solids or liquid at $${20^{\text{o}}}C$$   for example the heat capacity of calcium chloride $$\left( {CaC{l_2}} \right)$$   can be written as heat capacity of $$Ca + {2\,\,*}$$   heat capacity of $$Cl$$ .