CHEMISTRY GLOSSARY

ball mill    →   kuglični mlin

Ball mill is a grinder for reducing hard materials to powder. The grinding is carried out by the pounding and rolling of a charge of steel or ceramic balls carried within the cylinder. The cylinder rotates at a relatively slow speed, allowing the balls to cascade through the mill base, thus grinding or dispersing the materials.

Type of ball mills, centrifugal and planetary mills, are devices used to rapidly grind materials to colloidal fineness (approximately 1 μm and below) by developing high grinding energy via centrifugal and/or planetary action.

millimetre of mercury    →   milimetar živina stupca

Millimetre of mercury (mmHg) is a non-SI unit of pressure, equal to 133.322 Pa. The name is generally considered interchangeable with torr.

Millon’s reaction    →   Millonova reakcija

Millon’s reaction is used for testing proteins by the appearance of red colour which the proteins give by reacting with a solution of mercury in nitric acid.

colloid mill    →   koloidni mlin

Colloid mills are machines used to grind aggregates into very fine particles or to apply very high shearing within a fluid to produce colloid suspensions or emulsions in which the particle sizes are less than 1 micrometer. One type of colloid mill is called a disc mill, in which a mixture of a solid and liquid (or two liquids) is passed between two discs a small distance apart, which rotate very rapidly relative to each other. Applications of colloid mills occur in food processing, in paint manufacture, and in the pharmaceutical industry.

Brinell hardness    →   Brinellova tvrdoća

Brinell hardness is a scale for measuring the hardness of metals introduced around 1900 by Swedish metallurgist Johan Brinell (1849-1925). A small chromium steel ball is pressed into the surface of the metal by a load of known weight. The loading force is in the range of 300 N to 30 000 N. The ratio of the mass of the load in kilograms to the area of the depression formed in square millimetres is the Brinell Hardness Number.

Bunsen, Robert Wilhem    →   Bunsen, Robert Wilhem

Robert Wilhem Bunsen (1811-1899) is a German chemist who held professorships at Kassel, Marburg and Heidelberg. His early researches on organometallic compound of arsenic cost him an eye in an explosion. Bunsen's most important work was in developing several techniques used in separating, identifying, and measuring various chemical substances. He also improvement chemical battery for use in isolating quantities of pure metals - Bunsen battery.

The essential piece of laboratory equipment that has immortalized the name of Bunsen was not invented by him. Bunsen improved the burner's design, which had been invented by Faraday, to aid his endeavors in spectroscopy. Use of the Bunsen burner in conjunction with a glass prism led to the development of the spectroscope in collaboration with the German physicist Gustav Kirchoff and to the spectroscopic discovery of the elements rubidium (1860) and cesium (1861).

coal    →   ugljen

Coal is a black or brownish-black, combustible sedimentary rock, with 30 % (lignite) to 98 % (anthracite) carbon by weight, mixed with various amounts of water and small amounts of sulfur and nitrogen compounds. It is formed from plant matter that decayed in swamps and bogs that has been compressed and altered by geological processes over millions of years. Coal is primarily used as a fuel.

carbon    →   ugljik

Carbon has been known since ancient times. The origin of the name comes from the Latin word carbo meaning charcoal. Graphite form of carbon is a black, odourless, slippery solid. Graphite sublimes at 3825 °C. Diamond form is a clear or colored; an extremely hard solid. C60 is Buckminsterfullerine. Carbon black burns readily with oxidants. Carbon is made by burning organic compounds with insufficient oxygen. There are close to ten million known carbon compounds, many thousands of which are vital to organic and life processes. Radiocarbon dating uses the carbon-14 isotope to date old objects.

clay triangle    →   trokut za žarenje

Clay triangle is a piece of laboratory equipment used in the process of heating substances by a Bunsen burner (e.g. to support a crucible when it’s being heated).

crude oil    →   sirova nafta

Crude oil (petroleum) is a fossil fuel formed from plant and animal remains many million of years ago. It is occasionally found in springs or pools but is usually drilled from wells beneath the earth’s surface. Crude oil is a mixture of hydrocarbons with small quantities of other chemicals such as sulphur, nitrogen and oxygen. Crude is the raw material which is refined into petrol, heating oil, jet fuel, propane, petrochemicals, and other products.