CHEMISTRY GLOSSARY

Neel temperature    →   Neelova temperatura

Néel temperature (T_N) is the critical temperature above which an antiferromagnetic substance becomes paramagnetic. The phenomenon was discovered around 1930 by the French physicist L.E.F. Néel (1904-2000).

nonelectrolyte    →   neelektrolit

Nonelectrolytes are substances which in solutions do not dissociate into ions and they do not conduct electric current.

oligomer    →   oligomer

Oligomer is a substance consisting of molecules of intermediate relative molecular mass (molecular weight), the structure of which essentially comprises the multiple repetitions of units derived, actually or conceptually, from molecules of low relative molecular mass. In contrast to a polymer, the properties of an oligomer can vary significantly with the removal of one or a few of its units.

open system    →   otvoreni sustav

Open system is a system which can exchange matter and energy with the environment.

organic solvent    →   organsko otapalo

Organic solvent is an organic liquid in which organic (non-polar) substances melt.

organoleptic testing    →   organoleptičko ispitivanje

Organoleptic testing of matter is a testing of matter and material using the senses of sight, smell, taste and touch, used usually when buying groceries.

Nernst’s division law    →   Nernstov zakon razdjeljenja

Nernst’s division law states that a substance is divided between two solvents in a way that proportion of concentrations of that substance is at certain temperatures constant, under the condition that both solvents are in the same molecular state. Division coefficient is a proportion of substance concentration in solvents A i B at a defined temperature.

Appearance of division is used for substance extraction.

osmometry    →   osmometrija

Osmometry is a determination of the average molecular weight of a dissolved substance from measurements of osmotic pressure.

osmotic pressure    →   osmotski tlak

Osmotic pressure (Π) is the excess pressure necessary to maintain osmotic equilibrium between a solution and a pure solvent separated by a membrane permeable only to the solvent. In an ideal dilute solution

where c_B is the amount-of-substance concentration of the solute, R is the molar gas constant, and T the temperature.

overpotential    →   prenapon

Overpotential (η) is a potential that must be applied in an electrolytic cell in addition to the theoretical potential required to liberate a given substance at an electrode. The value depends on the electrode material and on the current density.