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acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

collodion

(Encyclopedia)collodion kəlōˈdēən [key], solution of pyroxylin in a mixture of alcohol and ether. Upon exposure to air, the solvents evaporate, leaving a thin, colorless, elastic film on any surface upon which...

aquaponics

(Encyclopedia)aquaponics, the growing of plants and the raising of fish by combining aquaculture with the techniques of hydroponics, usually on a small scale. Water containing fish waste matter is used as the nutri...

laudanum

(Encyclopedia)laudanum lôdˈənəm [key], tincture, or alcoholic solution, of opium, first compounded by Paracelsus in the 16th cent. Not then known to be addictive, the preparation was widely used up through the ...

Solvay process

(Encyclopedia)Solvay process [for Ernest Solvay], commercial process for the manufacture of sodium carbonate (washing soda). Ammonia and carbon dioxide are passed into a saturated sodium chloride solution to form s...

hydrogen fluoride

(Encyclopedia)hydrogen fluoride, chemical compound, HF, a colorless, fuming liquid or colorless gas that boils at 19.54℃. It is miscible with water and is soluble in benzene, toluene, and concentrated sulfuric ac...

calculus of variations

(Encyclopedia)calculus of variations, branch of mathematics concerned with finding maximum or minimum conditions for a relationship between two or more variables that depends not only on the variables themselves, a...

boric acid

(Encyclopedia)boric acid, any one of the three chemical compounds, orthoboric (or boracic) acid, metaboric acid, and tetraboric (or pyroboric) acid; the term often refers simply to orthoboric acid. The acids may be...

adsorption

(Encyclopedia)adsorption, adhesion of the molecules of liquids, gases, and dissolved substances to the surfaces of solids, as opposed to absorption, in which the molecules actually enter the absorbing medium (see a...

polarization of light

(Encyclopedia)polarization of light, orientation of the vibration pattern of light waves in a singular plane. Unpolarized light can be converted into a single polarized beam by means of the Nicol prism, a device ...