CHEMISTRY GLOSSARY

carbon dating    →   određivanje starosti radioaktivnim ugljikom

Carbon dating is used to the time passed since a living organism died. It is based on measuring the quantity of isotope of carbon-14 that is contained in all living organisms.

cellulose    →   celuloza

Cellulose, (C₆H₁₀O₅)_n, is a polysaccharide that consists of a long unbranched chain of glucose units linked by (1→4)-β-glycoside bonds. Nature uses cellulose primarily as a structural material to impart strength and rigidity to plants. Leaves, grasses, and cotton are primarily cellulose. The fibrous nature of extracted cellulose has led to its use in textile industry for the production of cotton, artificial silk, etc. Cellulose also serves as raw material for the manufacture of cellulose acetate, known commercially as acetate rayon, and cellulose nitrate, known as guncotton. Gunncotton is the major ingredient in smokeless powder, the explosive propellant used in artillery shells and in ammunition for firearms.

curium    →   kurij

Curium was discovered by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso (USA) in 1944. Named in honour of Pierre and Marie Curie. It is silvery, malleable, synthetic radioactive metal. So radioactive it glows in the dark. Curium was made by bombarding plutonium with helium ions.

deuterium    →   deuterij

Deuterium is an isotope of hydrogen that contains one neutron and one proton in its nucleus.

cobalt    →   kobalt

Cobalt was discovered by Georg Brandt (Germany) in 1735. The origin of the name comes from the German word kobald meaning goblin or evil spirit. It is hard, ductile, lustrous bluish-grey metal. Surfaces stable in air. Reacts over time with dilute acids. It has remarkable magnetic properties. Cobalt occurs in compounds with arsenic and sulfur as in cobaltine (CoAsS) and linneite (Co₃S₄). Pure cobalt is obtained as a by-product of refining nickel, copper and iron. Used in many hard alloys; for magnets, ceramics and special glasses. Radioactive cobalt-60 is used in cancer therapy.

cross-linking    →   umrežavanje

Cross-linking is an attachment of two chains of polymer molecules by bridges, composed of either an element, a group, or a compound, that join certain carbon atoms of the chains by primary chemical bonds, as indicated in the schematic diagram

Cross-linking occurs in nature in substances made up of polypeptide chains that are joined by the disulfide bonds of the cysteine residue, as in keratins or insulin. Cross-linking can be artificially effected, either adding a chemical substance (cross-linking agent), or by subjecting the polymer to high-energy radiation. Examples are: vulcanisation of rubber with sulphur, cross-linking of polystyrene with divinylbenzene, or cross-linking of polyethylene by means of high-energy radiation.

Cross-linking has the effect of changing a plastic from thermoplastic to thermosetting. Thus, it also increases strength, heat and electrical resistance, and especially resistance to solvents and other chemicals.

Curie    →   Curie

Maria Sklodowska-Curie (1867-1934) Polish-born French chemist who went to Paris in 1891. She married the physicist Pierre Curie (1859-1906) in 1985 and soon began work on seeking radioactive elements other than uranium in pitchblende (to account for its unexpectedly high radioactivity). By 1898 she had discovered radium and polonium although it took her years to purify them. In 1903 the Curies shared the Nobel Prize for physics with Henri Becquerel, who had discovered radioactivity.

darmstadtium    →   darmstadtij

Darmstadtium was discovered by S. Hofmann et al. collaboration at the Heavy Ion Research Laboratory (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany in November 1994. The title honours the Laboratory for Heavy Ion Research (called GSI) in Darmstadt, Germany, where the substance was first made. It is synthetic radioactive metal. The fusion-evaporation reaction using a ⁶²Ni beam on an isotopically enriched ²⁰⁸Pb target produced four chains of alpha-emitting nuclides following the presumed formation of ²⁶⁹110 + ¹n.

einsteinium    →   einsteinij

Einsteinium was discovered by Albert Ghiorso (USA) in 1952. Named in honour of Albert Einstein (1879-1955). It is synthetic radioactive metal. Einsteinium was made by bombarding uranium with neutrons.

fermium    →   fermij

Fermium was discovered by Albert Ghiorso (USA) in 1953. Named in honour of Enrico Fermi. It is synthetic radioactive metal. Fermium was produced by bombarding lighter transuranium elements with still lighter particles or by neutron capture.