CHEMISTRY GLOSSARY

contaminant    →   kontaminat

Contaminants are any physical, chemical, biological, or radiological substance or matter in water that may be harmful to human health or which degrade the palatability of water.

corticosteroid    →   kortikosteroid

Corticosteroids are general term for hormones produced by the adrenal gland. Includes cortisol and cortisone which regulate the use of nutrients in the body.

chemical potential    →   kemijski potencijal

For a mixture of substances, the chemical potential of constituent B (μ_B) is defined as the partial derivative of the Gibbs energy G with respect to the amount (number of moles) of B, with temperature, pressure, and amounts of all other constituents held constant.

Also called partial molar Gibbs energy. Components are in equilibrium if their chemical potentials are equal.

chemical reaction equation    →   jednadžba kemijske reakcije

Chemical reactions are symbolically shown with chemical equations. On the left side of the equation we write formulas or substance symbols which enter the chemical reaction, reactants. On the right side formulas or substance symbols which emerge from the chemical reaction, products, are writen.

Each chemical reaction leads to an equilibrium which is moved more or less to one side (left or right). Because of that, in reversible reactions instead of = sign two opposite arrows are put

In order to write down certain chemical reaction equation all reactants and all products and their stechiometric proportions must be known. (See Chemical reaction balancing)

chromium    →   krom

Chromium was discovered by Louis-Nicholas Vauquelin (France) in 1797. The origin of the name comes from the Greek word chroma meaning colour. It is very hard, crystalline, steel-grey metal. The pure metal has a blue-white colour. It is hard, brittle and corrosion-resistant at normal temperatures. Hexavalent compounds toxic by skin contact. The most important chromium mineral is chromite [Fe,Mg(CrO₄)]. Produced commercially by heating its ore in the presence of silicon or aluminium. Used to make stainless steel. It gives the colour to rubies and emeralds. Iron-nickel-chromium alloys in various percentages yield an incredible variety of the most important metals in modern technology.

critical mass    →   kritična masa

Critical mass is the minimum mass of a fissionable material (²³⁵U or ²³⁹Pu) that will initiate an uncontrolled chain reaction as in an atomic bomb. The critical mass of pure ²³⁹Pu is about 4.5 kg, and of ²³⁵U about 15 kg.

cryoscopic constant    →   krioskopska konstanta

Cryoscopic constant (E_f) is the constant that expresses the amount by which the freezing point T_f of a solvent is lowered by a non-dissociating solute, through the relation

where m is the molality of the solute.

crystallisation    →   kristalizacija

Crystallisation is process in which the melted substance from a saturated solution turns into solid substance (crystal).

decomposing    →   raščinjavanje

Decomposing in analytical chemistry means that a certain substance is converted, by melting it with a suitable melting medium (sodium carbonate, sodium hydroxide, sodium peroxide, ...) in the kind of compound which will afterwards that dissolve in water, acid or base very easily.

Clapeyron equation    →   Clapeyronova jednadžba

Clapeyron equation (also called the Clausius-Clapeyron equation) is a relation between pressure and temperature of two phases of a pure substance that are in equilibrium,

where Δ_trsS is the difference in entropy between the phases and Δ_trsV the corresponding difference in volume.