vapour pressure

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vapour pressure The pressure exerted by molecules of a substance in the vapour state, at equilibrium with molecules of the same substance in the liquid state, within a closed container. The magnitude of the vapour pressure exerted depends on the temperature and the identity of the liquid; it does not depend on the amount of liquid in the container. The saturated vapour pressure of water at 0°C is 610 Nm−2, rising to 2340 N m−2 at 20°C and 7380 N m−2 at 40°C. See also PARTIAL PRESSURE.

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