CHEMISTRY GLOSSARY

unsaturated fatty acid    →   nezasićena masna kiselina

Unsaturated fatty acid is a fatty acid whose carbon chain can absorb additional hydrogen atoms. Their carbon chain has one or more double or triple valence bond per molecule. The most important of these are:

ununbium    →   ununbij

Ununbium was discovered by S. Hofmann et al. collaboration at the Heavy Ion Research Laboratory (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany in February 1996. The new element has not yet been officially named, but it is known as ununbium, according to the system designated by the IUPAC for naming new elements. It is synthetic radioactive metal. Using the electromagnetic velocity filter SHIP, fusion-like residues of the reaction of ⁷⁰Zn with enriched ²⁰⁸Pb targets were measured. Two chains of localized alpha-emitters were identified as originating with ²⁷⁷112 + ¹n.

unununium    →   unununij

Unununium was discovered by S. Hofmann et al. collaboration at the Heavy Ion Research Laboratory (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany in December 1994. The new element has not yet been officially named, but it is known as unununium, according to the system designated by the IUPAC for naming new elements. It is synthetic radioactive metal. In bombardments of ²⁰⁹Bi targets with ⁶⁴Ni using the velocity selector SHIP facility to discriminate in favor of the fused product, ²⁷²111 + ¹n, three sets of localized alpha-decay chains were observed with position-sensitive detectors.

valence electron    →   valentni elektron

Valence electrons are electrons that can be actively involved in a chemical change, usually electrons in the outermost (valent) shell. For example, sodium’s ground state electron configuration is 1s² 2s² 2p⁶ 3s¹; the 3s electron is the only valence electron in the atom. Germanium (Ge) has the ground state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p²; the 4s and 4p electrons are the valence electrons.

valine    →   valin

Valine is hydrophobic amino acids with aliphatic side chain. It is a member of the branched-chain amino acid family, along with leucine and isoleucine. Valine differs from threonine by replacement of the hydroxyl group with a methyl substituent, but they are of roughly the same shape and volume. The nonpolar hydrophobic amino acids tend to cluster together within proteins, stabilizing protein structure by means of hydrophobic interactions. Valine is an essential amino acid, which means that it cannot be synthesized in the body and must be obtained through dietary sources.

• Abbreviations: Val, V
• IUPAC name: 2-amino-3-methylbutanoic acid
• Molecular formula: C₅H₁₁NO₂
• Molecular weight: 117.15 g/mol

van der Waals’ equation    →   van der Waalsova jednadžba

Van der Waals’ equation is an equation of state for real fluids which takes the form:

where p is pressure, V_m is molar volume, T is temperature, R is the molar gas constant, and a and b are characteristic parameters of the substance which describe the effect of attractive and repulsive intermolecular forces.

Volta, Alessandro    →   Volta, Alessandro

The Italian physicist Alessandro Giuseppe Antonio Anastasio Volta (1745-1827) was the inventor of the voltaic pile, the first electric battery (1800). In 1775 he invented the electrophorus, a device that, once electrically charged by having been rubbed, could transfer charge to other objects. Between 1776 and 1778, Volta discovered and isolated methane gas (CH₄). The electrical unit known as the volt was named in his honor.

Wagner tube    →   Wagnerova cijev

Wagner tube or drop catcher impedes the movement of distillate drops from the distillation flask to the condensing chamber.

X-ray tube    →   rendgenska cijev

X-ray tube is a cathode ray tube that focuses energetic streams of electrons on a metal target, causing the metal to emit X-rays. The basic principle of the X-ray tube has not changed significantly since Roentgen's 1895 discovery. Current applied to a metal cathode (about 50 000 V) produces free electrons. The X-rays are produced when the rapidly moving electrons are suddenly stopped as they strike the metal target of the tube.

xenon    →   ksenon

Xenon was discovered by Sir William Ramsay, Morris W. Travers (England) in 1898. The origin of the name comes from the Greek word xenos meaning stranger. It is heavy, colourless, odourless, noble gas. Reacts only with fluorine. Xenon is obtain from the small quantities in liquid air. Used for filling flash lamps and other powerful lamps. Electrical excitation of xenon produces a burst of brilliant white light. Also used in bubble chambers and modern nuclear power reactors.