CHEMISTRY GLOSSARY

surfactant    →   površinski aktivna tvar

Surfactants are substances which diminish the surface tension of liquids.

theories of catalysis    →   teorije katalize

Theories of catalysis explain the influence of the catalysts upon the rate of a reaction by describing the detailed mechanism by which the catalyst is involved in the steps of the chemical reaction.

weak base    →   slaba baza

Weak base is a base that only partially dissociates into ions in solution. Weak bases are weak electrolytes. Ammonia is an example of a weak base

supercritical fluid chromatography    →   superkritična fluidna kromatografija

Supercritical fluid chromatography (SFC) is a hybrid of gas and liquid chromatography. SFC is of importance because it permits the separation and determination of a group of compounds that are not conveniently handled by either gas or liquid chromatography. These compounds are either nonvolatile or thermally labile so that gas chromatography cannot be used and they do not contain functional groups that make possible detection by liquid chromatography. SFC has been applied to a wide variety of materials including natural prodcuts, drugs, foods, pesticides and herbicides, fossil fuels, explosives and propellants.

superoxide    →   superoksid

Superoxides are binary compounds containing oxygen in the -½ oxidation state. Sodium superoxide (NaO₂) can be prepared with high oxygen pressures, whereas the superoxides of rubidium, potassium, and cesium can be prepared directly by combustion in air. These compounds are yellow to orange paramagnetic solids. Superoxide ion, O₂^-, has an unpaired electron, is not particularly stable, and spontaneously decomposes into peroxide over time.

They are strong oxidising agents that vigorously hydrolyze (react with water) to produce superoxide and oxygen gas.

unequal-arm balance    →   vaga s različitim krakovima

The lever principle on which these scales are constructed is based on the law of physics that at equilibrium the force applied at one end of the lever multiplied by the length of the arm (distance from the fulcrum to the point where the force is applied) must be equal to the product of the force acting at the opposite end of the lever and the length of the other arm.

The unequal-arm balance is preferred for work when large amounts are to be weighed.

abrasive    →   abraziv

Abrasive is a very hard, brittle, heat-resistant substance that is used to grind the edges or rough surfaces of an object. Boron carbide, diamond, and corundum are abrasive.

accelerator    →   akcelerator

Accelerator is a device (machine) used for acceleration of charged particles (protons, deuterons, α-particles). Particles are accelerated under the influence of an electric field and with the help of a magnetic field are kept inside a certain space. When the particles reach enough acceleration (that is sufficient energy), they are directed on a target we wish to bomb. Best known types cyclotron, synchrotron, betatron.

Accelerator is a substance that increases the rate of chemical reaction, i.e. a catalyst.

activator    →   aktivator

Activator is a substance that increases the activity of a catalyst; for example, a substance that - by binding to an allosteric site on an enzyme - enables the active site of the enzyme to bind to the substrate.

activated charcoal    →   aktivni ugljen

Activated charcoal or activated carbon is charcoal that has been activated for adsorption by steaming or by heating in a vacuum. Charcoal is obtained by burning wood, nutshells, coconut husks or other materials. Charcoal becomes activated by heating it with steam to approximately 1000 °C in the absence of oxygen.

The chemical nature of amorphous carbon, combined with a high surface area makes it an ideal medium for the adsorption of organic chemicals. A single gram of such material can have 400 m² to 1 200 m² square meters of surface area. Activated charcoal is widely used to decolorize liquids, recover solvents, and remove toxins from water and air.