CHEMISTRY GLOSSARY

ampholyte    →   amfolit

Ampholyte is a substance than can act as either an acid, in the presence of a strong base, or a base, when in the presence of a strong acid.

amphoteric    →   amfoternost

Amphoteric is capable of acting either as an acid or base.

antifreeze    →   antifriz

Antifreeze is a substance added to the liquid (usually water) in the cooling systems of internal-combustion engines to lower its freezing point so that it does not solidify at sub-zero temperatures. The commonest antifreeze is ethane- 1.2-diol (ethylene glycol).

activity    →   aktivitet

Activity (a) is a thermodynamic function used in place of concentration in equilibrium constants for reactions involving nonideal gases and solutions. For the species i activity is defined as

where a_i is the activity of the species i, c_i is its molar concentration, and f_i is a dimensionless quantity called the activity coefficient.

air stripping    →   zračni striping

Air stripping is a process for the removal of volatile organic contaminants from groundwater. The groundwater flows downward inside a tower filled with materials (the packing) over a large surface area. Air is introduced at the bottom of the tower and is forced upward past the falling water. The volatiles evaporate from the water and are collected in air filters or released to the atmosphere.

alkali metal    →   alkalijski metal

Alkali metal is a term that refers to six elements: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). These elements make up group 1 of the periodic table of elements. They all form singly charged positive ions, and are extremely reactive. They react violently with water, forming hydroxides and releasing hydrogen gas and heat. Caesium and francium are the most reactive and lithium is the least.

allotrope    →   alotrop

Allotropes are the elements which exist in two or more different forms in the same physical state. Allotropes generally differ in physical properties and may also differ in chemical activity.

Diamond, graphite and fullerenes are three allotropes of the element carbon. Graphite is a soft, black, slippery substance; by contrast, diamond is one of the hardest substances known. The different properties of the allotropes arise from their chemical structures. Diamonds typically crystallize in the cubic crystal system and consist of tetrahedrally bonded carbon atoms. Graphite crystallizes in the hexagonal system. In the fullerenes, the carbon atoms taking the form of a hollow sphere, ellipsoid, or tube.

In some cases, the allotropes are stable over a temperature range, with a definite transition point at which one changes into the other. For instance, tin has two allotropes: white (metallic) tin stable above 13.2 °C and grey (nonmetallic) tin stable below 13.2 °C.

The term allotropes may also be used to refer to the molecular forms of an element. Ozone is a chemically active triatomic allotrope of the element oxygen.

ash    →   pepeo

Ash is an inorganic part of some matter or mixture which remains after the organic part has burnt up.

atom marking    →   markiranje atoma

Atom marking is a process of infusing radioactive isotopes in live organism, with the purpose of revealing a way, diffusion, or a role of certain substance.

autoignition temperature    →   temperatura samozapaljenja

Autoignition temperature is the minimum temperature required to initiate or cause self-sustained combustion in any substance in the absence of a spark or flame. This varies with the test method.