| Noun | 1. | Dalton's law of partial pressures - (chemistry and physics) law stating that the pressure exerted by a mixture of gases equals the sum of the partial pressures of the gases in the mixture; the pressure of a gas in a mixture equals the pressure it would exert if it occupied the same volume alone at the same temperaturelaw of nature, law - a generalization that describes recurring facts or events in nature; "the laws of thermodynamics" chemical science, chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions | |