CHEMISTRY GLOSSARY

Fajans’ rules    →   Fajansova pravila

Fajans’ rules, formulated by American chemist of Polish origin. Kazimierz Fajans (1887-1975), indicating the extent to which an ionic bond has covalent character caused by polarisation of the ions. Covalent character is more likely if:

1. the charge of the ions is high;

2. the positive ion is small or the negative ion is large;

3. the positive ion has an outer electron configuration that is not a noble- gas configuration.

secondary alcohol    →   sekundarni alkohol

Secondary alcohol is one in which the hydroxyl group (-OH) is attached to a secondary carbon atom (i.e. a carbon atom which has one hydrogen atom attached to it).

soldering    →   lemljenje

Soldering is a process of joining metallic surfaces with solder without melting the base material.

solvation    →   solvatacija

Solvation is the process by which solvent molecules surround and interact with solute ions or molecules.

terminal    →   terminalni

Terminal in chemistry means: the end of a polymer molecule and a point at which electron connections can easily be made or broken.

tertiary alcohol    →   tercijarni alkohol

Tertiary alcohols are aliphatic alcohols in which the hydroxyl group (-OH) is attached to a tertiary carbon atom.

thermodynamics    →   termodinamika

Thermodynamics is the scientific study of the interconversion of heat and other forms of energy.

unsaturated hydrocarbon    →   nezasićeni ugljikovodik

Unsaturated hydrocarbons are organic compounds containing double (alkenes) or triple (alkynes) bonds in their molecules.

fat    →   mast

Fats are esters of glycerol and long chain carboxylic acids. Fats occur widely in plants and animals as a means of storing food energy, having twice the calorific value of carbohydrates. Fats derived from plants and fish generally have a greater proportion of unsaturated fatty acids than those from mammals. Fats may be either solid or liquid at room temperature, depending on their structure and composition. Unsaturated fats are liquid at room temperature.

Plant oils may be hardened by the addition of hydrogen atoms, converting double bonds to single bonds. This process is known as hydrogenation. Hydrogenated vegetable oils are often present in margarine and other processed foods.

Alkali hydrolysis of fat with sodium hydroxide it gives glycerol and soap (i.e. a mixture of the sodium salts of the fatty acids).

free radical    →   slobodni radikal

Free radical is a molecular fragment having one or more unpaired electrons, usually short-lived and highly reactive. They can be produced by photolysis or pyrolysis in which a bond is broken without forming ions. In formulas, a free radical is conventionally indicated by a dot (·CH₃, ·SnH₃, ·Cl). Free radicals are known to be formed by ionising radiation and thus play a part in deleterious degradation effects that occur in irradiated tissue. They also act as initiators or intermediates in oxidation, combustion, photolysis, and polymerisation.