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density

(Encyclopedia)density, ratio of the mass of a substance to its volume, expressed, for example, in units of grams per cubic centimeter or pounds per cubic foot. The density of a pure substance varies little from sam...

American Standard Code for Information Interchange

(Encyclopedia)American Standard Code for Information Interchange: see ASCII. ...

melting point

(Encyclopedia)melting point, temperature at which a substance changes its state from solid to liquid. Under standard atmospheric pressure different pure crystalline solids will each melt at a different specific tem...

gas laws

(Encyclopedia)gas laws, physical laws describing the behavior of a gas under various conditions of pressure, volume, and temperature. Experimental results indicate that all real gases behave in approximately the sa...

phase diagram

(Encyclopedia)CE5 Phase diagram for a substance, like water, which expands on freezing phase diagram, graph that shows the relation between the solid, liquid, and gaseous states of a substance (see states of ma...

free energy

(Encyclopedia)free energy or Gibbs free energy, quantity derived from the relationships between heat and work studied in thermodynamics and used as a measure of the relative stability of a physical or chemical syst...

specific gravity

(Encyclopedia)specific gravity, ratio of the weight of a given volume of a substance to the weight of an equal volume of some reference substance, or, equivalently, the ratio of the masses of equal volumes of the t...

kinetic-molecular theory of gases

(Encyclopedia)kinetic-molecular theory of gases, physical theory that explains the behavior of gases on the basis of the following assumptions: (1) Any gas is composed of a very large number of very tiny particles ...

Le Châtelier's principle

(Encyclopedia)Le Châtelier's principle, chemical principle that states that if a system in equilibrium is disturbed by changes in determining factors, such as temperature, pressure, and concentration of components...

Saha, Meghnad

(Encyclopedia)Saha, Meghnad māgnädˈ säˈhä [key], 1893–1956, Indian physicist. He was a professor at Allahabad Univ. from 1923 to 1938 and a professor and physics department head at Calcutta Univ. from 1938....