CHEMISTRY GLOSSARY

invert sugar    →   invertni šećer

Invert sugar is a mixture of equal parts of glucose and fructose resulting from the hydrolysis of sucrose (saccharose). The name stemming from the fact that it rotates of plane polarized light in the opposite direction of sucrose. Sucrose is dextrorotatory - it rotates polarized light clockwise ([α]_D = +66.5°). Invert sugar rotates the plane of the polarized light counterclockwise ([α]_D = -22°) due to the strongly levorotatory nature of fructose ([α]_D = -92°).

Homemade artificial honey (invert sugar syrup): Dissolve two parts of household sugar (1 kg) with stirring in one part of water (0.5 kg) in a saucepan over low heat. Add 1 g of citric acid or the juice of one lemon to the mixture. Bring the ingredients to a slow boil. It can take anywhere between 15 minutes to 1 hour. The end result is sticky, golden syrup. Let it sit at room temperature until it is cool.

iodine    →   jod

Iodine was discovered by Bernard Courtois (France) in 1811. The origin of the name comes from the Greek word iodes meaning violet. It is shiny, black, non-metallic solid with characteristic odour. Sublimes easily and as a gas it is violet and intensely irritating to the eyes, nose and throat. Iodine occurs on land and in the sea in sodium and potassium compounds. Required in small amounts by humans. Once used as an antiseptic, but no longer due to its poisonous nature.

ion exchanger    →   ionski izmjenjivač

Ion-exchanger is a solid or liquid material containing ions that are exchangeable with other ions with a like charge that are present in a solution in which the material is insoluble. Ion-exchange resins consist of various copolymers having a cross-linked three-dimensional structure to which ionic groups have been attached.

natural caoutchouc    →   prirodni kaučuk

Natural caoutchouc is an addition polymer of isoprene. It is obtained from tropical plant of rubber-tree by coagulation of rubber-tree-milk.

natural gas    →   prirodni plin

Natural gas is a naturally occurring mixture of gaseous hydrocarbons. The approximate composition of natural gas is 85 % methane, 10 % ethane, 3 % propane, with lesser amounts of butane, and other higher alkanes. Natural gas is used as a fuel and for the manufacture of chemicals.

Navier-Stokes equations    →   Navier-Stokesove jednadžbe

Navier-Stokes equations are a set of complex equations for the motion of a viscous fluid subject to external forces.

ion selective electrode    →   ion selektivne elektrode

Ion selective electrode (ISE) is an electrode or electrode assembly with a potential that is dependent on the concentration of an ionic species in the test solution and is used for electroanalysis. Ion-selective electrodes are often membrane type electrodes.

ionic bond    →   ionska veza

Ionic bond is a strong force of attraction holding atoms together in a molecule or crystal. Typically chemical bonds have energies of about 100 kJ mol^-1. Ionic bond is a bond at which one of the participants, during the procedure of bonding, gives away its unpaired electrons to another atom so that both can achieve electron arrangement of the closest noble gas. In order to form an ionic bond one of the atoms must cross to the positively charged ion by losing certain number of electrons and the other atom must receive those electrons and cross to the negatively charged ion.

ionic strength    →   ionska jakost otopine

Ionic strength (μ or I) is a measure of the total concentration of ions in a solution, defined by

where z_i is the charge of ionic species i and c_i is its concentration.

ionisation    →   ionizacija

Ionisation is the process of producing ions. Certain molecules ionise in a solution; for example, acids ionise when dissolved in water.

Electron transfer also causes ionisation in certain reactions, for example sodium and chlorine react by transfer of a valence electron from the sodium atom to the chlorine atom to form the ions that constitute a sodium chloride crystal.