CHEMISTRY GLOSSARY

enzyme    →   enzim

Enzyme is a protein that acts as a catalyst in biochemical reactions. Each enzyme is specific to a particular reaction or a group of similar reactions. Many require the association of certain nonprotein cofactors in order to function. The molecule undergoing a reaction (the substrate) binds to a specific active site on the enzyme molecule to form a short-lived intermediate: this greatly increases (by a factor of up to 10²⁰) the rate at which the reaction proceeds to form the product.

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).

filtration    →   filtriranje

Filtration is a procedure in which liquids are separated from the precipitate by passing a suspension through the filter. The precipitate remains on the filter and through it the filtrate passes. Gaseous heterogeneous mixtures can also be filtrated.

transumutation    →   transmutacija

Transmutation is the conversion of one element into another by a process taking place in the nucleus.

vulcanisation    →   vulkanizacija

Vulcanisation (vulcanisation of rubber) is a process of combining rubber with sulphur or other substances that causes the polymer chains to crosslink, making them stronger and more elastic.

water purification    →   pročišćavanje vode

Water purification is a procedure of harmful substances removal in order to obtain pure drinking-water.

water softening    →   omekšavanje vode

Water softening is a process in which calcium and magnesium ions are removed from water. It is usually done by ion exchanger which exchanges removed ions with sodium ones.

welding    →   varenje

Welding is a process of joining of two metal surfaces that have been heated, melted, and fused together.

yeast    →   kvasac

Yeasts are a group of unicellular fungi which exist almost everywhere in nature. There are about 1500 species currently known to science. Yeast contains an enzyme called cimase which catalyses change of glucose in ethanol in the process of alcoholic fermentation.

fractional distillation    →   frakcijska destilacija

Fractional distillation is a procedure in which liquids of close boiling points are separated. It is conducted in fraction or rectification columns in a way that vapour phase created by distillation is condensed and the condensate thus obtained is redistilled. The procedure is repeated several times. Vapour phase always contains more volatile component than the liquid phase, at top of the column vapour of clean volatile component gets out and at the bottom of the column liquid of nonvolatile component.