Exchange Exchange is a marketplace in which shares, options and futures on stocks, bonds, commodities, and indexes are traded. Principal U.S. stock exchanges are: New York Stock Exchange (NYSE), American Stock Exchange (AMEX), and National Association of Securities Dealers Automatic Quotation System (Nasdaq).
From Wikipedia, the free encyclopedia. The DielsâAlder reaction is an organic chemical reaction (specifically, a [4+2] cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system.n a normal demand DielsâAlder reaction, the dienophile has an electron-withdrawing group in conjugation with the alkene; in an inverse-demand scenario, the dienophile is conjugated with an electron-donating group.
Photosynthesis and chemosynthesis are both processes by which organisms produce food; photosynthesis is powered by sunlight while chemosynthesis runs on chemical energy.hemosynthesis is the use of energy released by inorganic chemical reactions to produce food. Chemosynthesis is at the heart of deep-sea communities, sustaining life in absolute darkness, where sunlight does not penetrate.