CHEMISTRY GLOSSARY

dynamic equilibrium    →   dinamička ravnoteža

Dynamic equilibrium is established when two opposing processes are occurring at precisely the same rate, so that there is no apparent change in the system over long periods of time.

chromatography    →   kromatografija

Chromatography is a method of separation of the components of a sample in which the components are distributed between two phases, one of which is stationary while the other moves. In gas chromatography, the gas moves over a liquid or solid stationary phase. In liquid chromatography, the liquid mixture moves through another liquid, a solid, or a gel. The mechanism of separation of components may be adsorption, differential solubility, ion-exchange, permeation, or other mechanisms.

collision theory    →   teorija sudara

Collision theory is theory that explains how chemical reactions take place and why rates of reaction alter. For a reaction to occur the reactant particles must collide. Only a certain fraction of the total collisions cause chemical change; these are called successful collisions. The successful collisions have sufficient energy (activation energy) at the moment of impact to break the existing bonds and form new bonds, resulting in the products of the reaction. Increasing the concentration of the reactants and raising the temperature bring about more collisions and therefore more successful collisions, increasing the rate of reaction.

column chromatography    →   kromatografija u koloni

Column chromatography is generally used as a purification technique: it isolates desired compounds from a mixture. In column chromatography, the stationary phase, a solid adsorbent, is placed in a vertical column. The mobile phase, a liquid, is added to the top and flows down through the column by either gravity or external pressure. The mobile phase can be a gas or a liquid which gives rise to the two basic forms of chromatography, namely, gas chromatography (GC) and liquid chromatography (LC).

eutectic    →   eutektik

Eutectic is a solid solution consisting of two or more substances and having the lowest freezing point of any possible mixture of these components.

Eutectic point is the lowest temperature at which the eutectic mixture can exist in a liquid phase. A liquid having the eutectic composition will freeze at a single temperature without a change of composition.

conditional electrode potential    →   uvjetni elektrodni potencijal

Conditional or formal electrode potential (E°’) is equal to electrode potential (E) when overall concentrations of oxidised and reduced form in all its forms in a solution are equal to one. Conditional electrode potential includes all effects made by reactions that do not take part in the electron exchange, but lead to change of ion power, changes of pH, hydrolysis, complexing, precipitating, etc.

At 298 K (25 °C) and by converting natural (Napierian) logarithms into decimal (common, or Briggian) logarithms, Nernst’s equation for electrode potential can be written as follows:

Coulomb’s law    →   Coulombov zakon

Coulomb’s law is the statement that the force F between two electrical charges q₁ and q₂ separated by a distance r is

where ε_o is the permittivity of a vacuum, equal to

Fermi level    →   Fermijev nivo

Fermi level is the highest energy of occupied states in a solid at zero temperature. The Fermi level in conductors lies in the conduction band, in insulators it lies in the valence band, and in semiconductors it falls in the gap between the conduction band and the valence band. It was named after the Italian physicst Enrico Fermi (1901 - 1954).

fermion    →   fermioni

Fermion is any particle with spin equal to an odd multiple of 1/2. Fermion is a particle that obeys Fermi-Dirac statistics, e.g. electron, proton, neutron, muon, etc.

ferric    →   feri

Ferric is the term or prefix used to denote compounds of iron in which iron is in the trivalent, Fe(III), state, for example, ferric chloride, FeCl₃.