Dulong and Petit's Law (OF ATOMIC HEAT)

The specific heat of an element is inversely proportional to its atomic weight, or the product of the specific heat and the atomic weight is equal to a constant. This constant is called atomic heat; it is approximately equal to 6.4. If we take as many grams of any element as are numerically equal to its atomic weight, and call this amount a gram-atom, the atomic heat of the element is the number of calories of heat nece ary to raise the temperature of one gram-atom 1o C. In the case of compounds, we speak of the molecular heat, which is approximately equal to the sum of the atomic heats of the component elements. The above law when applied to compounds is known as "Naumann's Law."