الرئيسية » Simplified Chemistry (صفحه 23)

Simplified Chemistry

absolute configuration

A way of denoting the absolute structure of an optical isomer . Two conventions are in use: The D-L convention relates the structure of the molecule to some reference molecule. In the case of sugars and similar compounds, the dextrorotatory form of glyceraldehyde (HOCH2CH(OH)CHO , 2,3-dihydroxy­propanal) was used. The rule …

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absolute

1. Not dependent on or relative to anything else, e.g. absolute zero. 2. Denoting a temperature measured on an absolute scale, a scale of temperature based on absolute zero. The usual absolute scale now is that of thermodynamic temperature; its unit, the kelvin, was formerly called the degree absolute (0A) …

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ab-initio calculation

A method of calculating atomic and molecular structure directly from the first principles of quantum mechanics, without using quantities derived from experiment (such as ionization energies found by spectroscopy) as parameters. Ab-initio calculations require a large amount of numerical computation; the amount of computing time required increases rapidly as the size …

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Hybridization

Hybridization :  is a mathematical concept which implies for the mixing of various atomic orbitals with slightly different energies of the same atom to construct equal number of hybrid (mixed) orbitals of equal energy, in a molecule. For an isolated atom, however. the hybridization has no meaning. Hybridization involves promotion …

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Chemical Bonding

Chemical bond: The attractive force which holds together the constituent atoms of chemical compounds is called chemical bond. Combination of atoms: It. is universal law of nature that systems with lower energy are more stable. So atoms combine to form a molecule because it has a· lower energy i.e., more …

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