CHEMISTRY GLOSSARY

lux    →   luks

Lux (lx) is the SI derived unit of illuminance. The lux is the illuminance produced by a luminous flux of one lumen uniformly distributed over a surface of one square metre (1 lx = 1 lm·m^-2).

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electron microscope    →   elektronski mikroskop

Electron microscope is a form of microscope that uses a beam of electrons instead of a beam of light (as in the optical microscope) to form a large image of a very small object. In optical microscopes the resolution is limited by the wavelength of the light. High-energy electrons, however, can be associated with a considerably shorter wavelength than light; for example, electrons accelerated to energy of 10⁵ electronvolts have a wavelength of 0.004 nm enabling a resolution of from 0.2 nm to 0.5 nm to be achieved.

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fluorine    →   fluor

Fluorine was discovered by Henri Moissan (France) in 1886. The origin of the name comes from the Latin word fluere meaning to flow. It is pale yellow to greenish gas, with an irritating pungent odour. Extremely reactive, flammable gas. Reacts violently with many materials. Toxic by inhalation or ingestion. Does not occur uncombined in nature. Fluorine is found in the minerals fluorite (CaF₂) and cryolite (Na₃AlF₆). Electrolysis of hydrofluoric acid (HF) or potassium acid fluoride (KHF₂) is the only practical method of commercial production. Used in refrigerants and other fluorocarbons. Also in toothpaste as sodium fluoride (NaF).

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fructose    →   fruktoza

Fructose (fruit sugar) is a ketohexose (a six-carbon ketonic sugar), which occurs in sweet fruits and honey. Glucose and fructose have the same molecular formula, C₆H₁₂O₆, but have different structures. Pure, dry fructose is a very sweet, white, odorless, crystalline solid. Fructose is one of the sweetest of all sugars and is combined with glucose to make sucrose, or common table sugar. An older common name for fructose is levulose, after its levorotatory property of rotating plane polarized light to the left (in contrast to glucose which is dextrorotatory). The polysaccharide inulin is a polymer of fructose.

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gallium    →   galij

Gallium was discovered by Lecoq de Boisbaudran (France) in 1875. The origin of the name comes from the Latin word Gallia meaning France. It is soft, blue-white metal. Stable in air and water. Reacts violently with chlorine and bromine. Gallium is found throughout the crust in minerals like bauxite, germanite and coal. Used in semiconductor production. It us used in making LED’s (light-emitting diodes) and GaAs laser diodes.

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monochromator    →   monokromator

Monochromator (from the Greek words mono and chroma meaning single and colour) is an optical device based on dispersion of light by one or more prisms or diffraction gratings into its constituent wavelengths, which are utilized in turn.

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neon    →   neon

Neon was discovered by Sir William Ramsay and Morris W. Travers (England) in 1898. The origin of the name comes from the Greek word neon meaning new. It is colourless, odourless inert gas. Non-reactive even with fluorine. Fourth most abundant element in the universe. Neon is obtained by liquefaction of air and separated from the other gases by fractional distillation. Primarily for lighting.

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invert sugar    →   invertni šećer

Invert sugar is a mixture of equal parts of glucose and fructose resulting from the hydrolysis of sucrose (saccharose). The name stemming from the fact that it rotates of plane polarized light in the opposite direction of sucrose. Sucrose is dextrorotatory - it rotates polarized light clockwise ([α]_D = +66.5°). Invert sugar rotates the plane of the polarized light counterclockwise ([α]_D = -22°) due to the strongly levorotatory nature of fructose ([α]_D = -92°).

Homemade artificial honey (invert sugar syrup): Dissolve two parts of household sugar (1 kg) with stirring in one part of water (0.5 kg) in a saucepan over low heat. Add 1 g of citric acid or the juice of one lemon to the mixture. Bring the ingredients to a slow boil. It can take anywhere between 15 minutes to 1 hour. The end result is sticky, golden syrup. Let it sit at room temperature until it is cool.

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racemic mixture    →   racematna smjesa

Racemic mixture is a mixture of dextrorotatory and levorotatory optically active isomers in equal amounts. Because the two enantiomers rotate plane-polarised light in opposite directions, a racemic mixture does not rotate plane-polarised light. These mixtures are prefixed by ± or dl-.

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Raman effect    →   Ramanov efekt

Raman effect is a type of scattering of electromagnetic radiation in which light suffers a change in frequency and a change in phase as it passes through a material medium. Named according to the Indian physicist C. V. Raman (1889-1970). The intensity of Raman scattering is about one-thousandth of that in Rayleigh scattering in liquids.

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