CHEMISTRY GLOSSARY

autoxidation    →   autooksidacija

Autoxidation, autooxidation is a oxidation is caused by exposure to air. Rust is an example of autoxidation. Autoxidation makes ether taken from half-filled bottles very dangerous, because air oxidises ether to highly explosive organic peroxides.

barrel    →   barel

Barrel (US, petrol) is an American unit of capacity usually employed in the petroleum industry and trading in fuels (barell = 158.987 294 9 L).

battery acid    →   baterijska kiselina

Battery acid is a solution of approximately 6 mol L^-1 sulphuric acid used in the lead storage battery

biogas    →   bioplin

Biogas is a mixture of methane and carbon dioxide resulting from the anaerobic decomposition of such waste materials as domestic, industrial, and agricultural sewage. Methanogenic bacteria carry out the decomposition; these obligate anaerobes produce methane, the main component of biogas, which can be collected and used as an energy source for domestic processes, such as heating, cooking, and lighting.

blank determination    →   slijepa proba

Blank determination is a procedure of determining which follows all steps of analysis but in the absence of a sample. It is used for detection and compensation of systematic analysis mistakes.

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.

angular momentum    →   moment količine gibanja

Angular momentum is a physical quantity defined for rotating motion (in analogy to momentum that is defined for linear motion). If a body rotates around a specified axis, its angular momentum equals

Where I is the rotational inertia concerning that axis and ω is the angular velocity of the body.

Angular momentum can also be defined for a point-like body concerning a specified origin (in that case, it is not necessary that the point-like body undergoes circular motion). Rotational inertia of the point-like body, concerning that origin equals:

Where m is the mass of the body and r is its distance from the origin.

cadmium coating    →   kadmiranje

Cadmium coating is a galvanic coating of metallic objects with a cadmium layer for corrosion resistance.

calibration    →   kalibracija

Calibration is correcting a measuring instrument by measuring values whose true values are known. Calibration minimises systematic error.

carmine    →   karmin

Carmine is a bright crimson red colour gained from a type of plant lice. Its main ingredient is carmine acid, and it is often used in the colouring of cosmetics, medicines, foods.