CHEMISTRY GLOSSARY

protein    →   bjelančevina

Proteins are natural organic compounds of animal or herbal origin, essential in diet. They are natural polymers developed from a crowd of interconnecting monomers of amino acids, with relative molecular masses amounting up to a few million.

reactivity series    →   reaktivni niz

Reactivity series or activity series is a series of elements (usually metals) ranked by their reactivity degree, made for comparison of reactions of elements with other substances, e.g. acids and oxygen.

regeneration    →   regeneracija

Regeneration is the process of restoring an ion exchange medium to a usable state after exhaustion. The cation exchanger is normally regenerated with hydrochloric acid and the anion exchanger with sodium hydroxide.

salt    →   soli

Salt is an ionic compound formed by the reaction of an acid and a base. The reaction of sodium hidroxide to hydrochloric acid gives sodium chloride

fluorine    →   fluor

Fluorine was discovered by Henri Moissan (France) in 1886. The origin of the name comes from the Latin word fluere meaning to flow. It is pale yellow to greenish gas, with an irritating pungent odour. Extremely reactive, flammable gas. Reacts violently with many materials. Toxic by inhalation or ingestion. Does not occur uncombined in nature. Fluorine is found in the minerals fluorite (CaF₂) and cryolite (Na₃AlF₆). Electrolysis of hydrofluoric acid (HF) or potassium acid fluoride (KHF₂) is the only practical method of commercial production. Used in refrigerants and other fluorocarbons. Also in toothpaste as sodium fluoride (NaF).

fuel cell    →   gorivi članak

Fuel cell is a device that converts chemical energy into electrical energy. It is different from a battery in that the energy conversion continues as long as fuel and oxidising agent are fed to the fuel cell; that is, in principle indefinitely. (A battery is manufactured with a limited amount of chemicals, and it is exhausted when all the chemicals have reacted.) It is a galvanic cell where spontaneous chemical reactions occur at the electrodes. The fuel is oxidised at the anode, and the oxidising agent (almost always oxygen or air) is reduced at the cathode. Presently, the most commonly used fuel is hydrogen. More conventional fuels (e.g., petrol or natural gas) must be converted (reformed) into hydrogen before they can be utilised in a fuel cell.

Some fuel cells employ an aqueous solution as electrolyte, that can be either acidic or basic (alkaline), or an ion-exchange membrane soaked in aqueous solution can act as the electrolyte. These fuel cells operate at relatively low temperatures (from room temperature to not much above the boiling point of water). Some fuel cells employ molten salts (especially carbonates) as electrolytes and have to operate at temperatures of several hundred degrees centigrade (Celsius). Others employ ionically conductive solids as electrolyte and must operate close to 1 000 °C.

gadolinium    →   gadolinij

Gadolinium was discovered by Jean de Marignac (France) in 1880. Named after the mineral gadolinite, named for J. Gadolin, a Finnish chemist and mineralogist. It is soft, ductile, silvery-white metal. Reacts slowly with water and oxygen. Dissolves in acids. Metal ignites and burns readily. Gadolinium is found with other rare earths in gadolinite and monazite sand. Used in steel alloying agents and the manufacture of electronic components.

saponification    →   saponifikacija

Saponification is a proces of hydrolysis of esters using hot sodium hydroxide solution to produce the salt of a carboxylic acid. Saponification usually refers to the hydrolysis of esters of fatty acids to manufacture soaps.

soap    →   sapun

Soap is a salt of a fatty acid. For example, sodium stearate is a soap made by neutralizing stearic acid. Commercial soaps are mixtures of fatty acid salts.

wax    →   vosak

Wax is an ester formed from long-chain fatty acids and alcohols that is usually solid at room temperature.