Formers

There are two types of measurement errors, systematic and random. The former are due to an inherent bias in the measurement procedure, resulting in a consistent deviation of the experimental measurement from its true value. An experimenter s skill and experience provide the only means of consistently detecting and avoiding systematic errors. By contrast, random or statistical errors are assumed to result from a large number of small disturbances. Such errors tend to have simple distributions subject to statistical characterization. 

An arrangement is to be chosen to inhibit the side reaction, i.e., give low selectivity losses. The side reaction is suppressed by starving the reactor of either monochlorodecane or chlorine. Since the reactor is designed to produce monochlorodecane, the former option is not practical. However, it is practical to use an excess of decane. 

Atomic weights were formerly defined relative to one atom of H and then to 0. 

Alternatively, in a photochemical reaction a molecule absorbs light. This results in it possessing more energy than an ordinary molecule and, consequently, more reactivity. However, collision of this activated molecule with another molecule may cause the former to lose its energy without reacting. The activated molecule is said to have undergone a deactivating collision and has itself become deactivated. 

Enzymes are classified in terms of the reactions which they catalyse and were formerly named by adding the suffix ase to the substrate or to the process of the reaction. In order to clarify the confusing nomenclature a system has been developed by the International Union of Biochemistry and the International Union of Pure and Applied Chemistry (see Enzyme Nomenclature , Elsevier, 1973). The enzymes are classified into divisions based on the type of reaction catalysed and the particular substrate. The suffix ase is retained and recommended trivial names and systematic names for classification are usually given when quoting a particular enzyme. Any one particular enzyme has a specific code number based upon the new classification. 

The other tetritols were formerly called d-and /-erythritol, but have been renamed L-and D-threitol respectively. A racemic form can also be prepared,... 

HOaQCHjlfiCOiH, CSH14O4. Important dicarboxylic acid obtained by oxidizing ricino-leic acid (from castor oil) also obtained by oxidation of cyclo-octene or cyclo-octadiene formerly obtained from cork. Used in the formation of alkyd resins and polyamides. Esters are used as plasticizers and heavy duty lubricants and oils. 

Commercially, xylene is obtained by the catalytic reforming of naphthenes in the presence of hydrogen see toluene) or was formerly obtained from coal tar. The material so-produced is suitable for use as a solvent or gasoline ingredient, these uses accounting for a large part of xylene consumption. If xylene is required as a chemical, separation into the iso-... 

The first requirement is a source of infrared radiation that emits all frequencies of the spectral range being studied. This polychromatic beam is analyzed by a monochromator, formerly a system of prisms, today diffraction gratings. The movement of the monochromator causes the spectrum from the source to scan across an exit slit onto the detector. This kind of spectrometer in which the range of wavelengths is swept as a function of time and monochromator movement is called the dispersive type. 

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