CHEMISTRY GLOSSARY

beta-glucan    →   beta-glukan

Beta-glucans are are naturally occurring polysaccharides that contain only glucose as structural components, and are linked with β-glycosidic bonds. They is the most known powerful immune stimulant. The most active forms of β-glucans are those comprising D-glucose units with β(1→3) links and with short side-chains of D-glucose attached at the β(1→6) position. These are referred to as beta-1,3/1,6 glucan. They are a major component of soluble dietary fiber, which can be found in cereal grains (oats, barley, wheat), yeast, and certain mushrooms (shiitake, maitake).

binary solution    →   binarna otopina

Binary solution is a mixture of two liquids that are completely miscible one with another. The boiling point of binary solution depends upon the solution composition and there can be three cases:

1. the boiling points of solutions of all compositions lie between the boiling points of clean liquids

2. the boiling points of solutions of any composition lie above the boiling points of clean liquids

3. the boiling points of solutions of some compositions lie below the boiling points of clean liquids

Biot-Savart law    →   Biot-Savartov zakon

The magnetic field B due to a current-carrying conductor can be determined by Biot-Savart law. The contribution to magnetic field set up at distance r by the current element IdL is given by expression:

where μ₀ is permeability constant. It plays a role in magnetic problems equivalent to the role of permittivity constant μ₀ in electrostatics problems. In order to obtain B, contributions of all current elements have to be integrated. In case of a long straight conductor, carrying current I, Biot-Savart law gives:

SI unit for magnetic field B is tesla (T).

Permaeability constant μ₀ has value 4π×10^-7 T m A^-1.

bismuth    →   bizmut

Bismuth was discovered by Claude Geoffroy (France) in 1753. The origin of the name comes from the German words Weisse Masse meaning white mass; now spelled wismut and bisemutum. It is hard, brittle, steel-grey metal with a pink tint. Stable in oxygen and water. Dissolves in concentrated nitric acid. Bismuth can be found free in nature and in minerals like bismuthine (Bi₂S₃) and in bismuth ochre (Bi₂O₃) Main use is in pharmaceuticals and low melting point alloys used as fuses.

bomb calorimeter    →   kalorimetrijska bomba

Bomb calorimeter is a type of constant-volume calorimeter used in measuring the heat of combustion of samples which can be burned in oxygen. Four essential parts are required in any bomb calorimeter:

1. a bomb or vessel in which the combustible charges can be burned,
2. a bucket or container for holding the bomb in a measured quantity of water, together with a stirring mechanism,
3. an insulating jacket to protect the bucket from transient thermal stresses during the combustion process, and
4. a thermometer or other sensor for measuring temperature changes within the bucket.

borane    →   borani

Borane is any of the group of compounds of boron and hydrogen (B₂H₆, B₄H₁₀, B₅H₉, B₅H₁₁...), many of which can be prepared by action of acid on magnesium boride (Mg₃B₂). Boranes are a remarkable group of compounds in that their structures cannot be described using the conventional two-electron covalent bond model.

boron    →   bor

Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy (England) and independently by Joseph-Louis Gay-Lussac (France) and L. J. Thenard (France). The origin of the name comes from the Arabic word buraq and the Persian word burah meaning boraks. It is hard, brittle, lustrous black semimetal. Unreactive with oxygen, water, alkalis or acids. Combines with most metals to form borides. Boron is obtained from kernite, a kind of borax (Na₂B₄O₇·10H₂O). High purity boron is produced by electrolysis of molten potassium fluroborate and potassium chloride (KCl). Amorphous boron is used in pyrotechnic flares to provide a distinctive green color and in rockets as an igniter.

chemical glass    →   kemijsko staklo

Chemical glass is a special, resilient glass used in production of chemical vessels; it is composed of quartz and boron, barium, zinc and aluminium oxides.

chemical property    →   kemijsko svojstvo

Chemical property is a property observed when a substance undergoes a transformation into one or more new substances. Measurement of a chemical property involves a chemical change. For example, determining the flammability of petrol involves burning it, producing carbon dioxide and water.

chlorination    →   kloriranje

1. Chlorination is an addition or substitution of chlorine in organic compounds.

2. Chlorination is a sterilisation of drinking and swimming pool water or oxidation of undesirable impurities, using chlorine or its compounds.