CHEMISTRY GLOSSARY

contaminant    →   kontaminat

Contaminants are any physical, chemical, biological, or radiological substance or matter in water that may be harmful to human health or which degrade the palatability of water.

decomposing    →   raščinjavanje

Decomposing in analytical chemistry means that a certain substance is converted, by melting it with a suitable melting medium (sodium carbonate, sodium hydroxide, sodium peroxide, ...) in the kind of compound which will afterwards that dissolve in water, acid or base very easily.

dehydration    →   dehidracija

Dehydration is the removal of water from a substance

detergent    →   deterdžent

Detergent is a substance added to water to improve its cleaning properties. Although water is a powerful solvent for many compounds, it will not dissolve grease and natural oils. Detergents are compounds that cause such nonpolar substances to go into solution in water. Soap is the original example, owing its action to the presence of ions formed from long-chain fatty acids ion (e.g. stearat ion, CH₃(CH₂)₁₆COO^-).

barium    →   barij

Barium was discovered by Sir Humphry Davy (England) in 1808. The origin of the name comes from the Greek word barys meaning heavy. It is soft, slightly malleable, silvery-white metal. Attacked by air and water. Soluble compounds toxic by ingestion. Barium is found in barytine (BaSO₄) and witherite (BaCO₃), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure. Barite, or barium sulfate (BaSO₄), when ground is used as a filter for rubber, plastics and resins. It is insoluble in water and so is used in X-rays of the digestive system. Barium nitrate, Ba(NO₃)₂, burns brilliant green and is used in fireworks.

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.

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.

dilution    →   razrjeđivanje

Dilution is the action of diluting or reducing the strength or concentration of a liquid, usually by the addition of water.

emulsion    →   emulzija

Emulsion is a colloidal system in which the dispersed and continuous phases are both liquids (e.g. oil in water or water in oil). Such systems require an emulsifying agent to stabilize the dispersed particles.