Source : WordNet®

law of partial pressures
     n : (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 temperature [syn: {Dalton's law}, {Dalton's law of
         partial pressures}]