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How did the Dulong-Petit law help scientists estimate atomic weights?
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heating
In a thermoelectric generating system a heat sourceāusually fueled by coal, oil, or gasāis used within a boiler to convert water to high-pressure steam. The steam expands and turns the blades of a turbine, which turns the armature of a generator, producing electric power. A condenser converts any remaining steam to water, and a pump returns the water to the boiler.
The Dulong-Petit law states that the gram-atomic heat capacityācalculated as the product of an element's specific heat and its atomic weightāis approximately a constant value of six calories per gram atom.1
Because this value is constant for solid elements, scientists were able to use it as an empirical tool to estimate atomic weights. By measuring the specific heat of a solid element, researchers could rearrange the relationship to solve for the unknown atomic weight. While the law was later refined to apply primarily to metallic elements and is now considered an approximation for intermediately high temperatures, it played a crucial role in the early determination of atomic weights.12