CHEMISTRY GLOSSARY

antioxidant    →   antioksidans

Antioxidants are compounds that slow down oxidation processes that degrade foods, fuels, rubber, plastic, and other materials. Antioxidants like butylated hydroxyanisole (BHA), are added to food to prevent fats from becoming rancid and to minimize decomposition of vitamins and essential fatty acids; they work by scavenging destructive free radicals from the food.

artificial radioactive isotope    →   umjetni radioaktivni izotop

Artificial radioactive isotopes are formed when an atom is bombed with an accelerator or exposing it to slow moving neutrons in a nuclear reactor. In this way isotopes (radionuclides) are obtained which are non-existent in nature because of their unstability and radioactive transition into stable isotopes. Most important radioactive isotopes are:

Radioactive isotope of cobalt is formed when ordinary metal cobalt is bombed with neutrons in a nuclear reactor.

Radioactive isotope of phosphorus is formed when ordinary phosphorus is bombed with deuterons produced in cyclotron.

radioactive isotope of carbon is formed when a nitrogen is bombed with slow moving neutrons in a nuclear reactor. It is mostly used as a radioactive indicator.

autocatalysis    →   autokataliza

Autocatalysis is a reaction in which its product can act as a catalyst. Oxalate oxidation with permanganate in an acid solution is a slow reaction

Mn²⁺-ions catalyse this reaction. When enough Mn²⁺-ions are created, the reaction occurs instantly.

fractional crystallisation    →   frakcijska kristalizacija

Fractional crystallisation is a method of separating a mixture of soluble solids by dissolving them in a suitable hot solvent and then lowering the temperature slowly. The least soluble component will crystallise out first, leaving the other components in the solution. By controlling the temperature, it is sometimes possible to remove each component in turn.

neptunium    →   neptunij

Neptunium was discovered by Edwin M. McMillan and P. H. Abelson (USA) in 1940. Named after the planet Neptune. It is rare, silvery radioactive metal. Resists alkalis; reacts with oxygen and acids. Attacked by steam. Radiotoxic. Neptunium was produced by bombarding uranium with slow neutrons.

ricin    →   ricin

Ricin is a toxin derived from the castor bean. It can be spread in aerosol or liquid form. It causes blood poisoning and leads to the collapse of the circulatory system and a slow death.

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.

erbium    →   erbij

Erbium was discovered by Carl Gustaf Mosander (Sweden) in 1843. Named after Ytterby, a village in Sweden. It is soft, malleable, silvery metal. Reacts slowly with water. Dissolves in acids. Metal ignites and burns readily. Erbium is found with other heavier rare earths in xenotime and euxenite. Erbium oxide is used in ceramics to obtain a pink glaze. Also a few uses in the nuclear industry and as an alloying agent for other exotic metals.

gadolinium    →   gadolinij

Gadolinium was discovered by Jean de Marignac (France) in 1880. Named after the mineral gadolinite, named for J. Gadolin, a Finnish chemist and mineralogist. It is soft, ductile, silvery-white metal. Reacts slowly with water and oxygen. Dissolves in acids. Metal ignites and burns readily. Gadolinium is found with other rare earths in gadolinite and monazite sand. Used in steel alloying agents and the manufacture of electronic components.

gas washing bottle    →   boca ispiralica

Gas washing bottle or Drechsel bottle provide an inexpensive but effective method for washing or drying gases. The gas enters the bottle through the top of the central vertical tube, the lower end of which is below the surface of the washing medium. To maximize surface area contact of the gas to the liquid, a gas stream is slowly blown into the vessel through the fritted glass tip so that it breaks up the gas into many tiny bubbles. After bubbling through the medium, the gas rises to the top and exits through the side tube. It is named after the German chemist Edmund Drechsel (1843-1897).