CHEMISTRY GLOSSARY

gold    →   zlato

Gold has been known since ancient times. The origin of the name comes from the Latin word aurum meaning gold. It is soft, malleable, bright yellow metal. Unaffected by air, water, alkalis and most acids. Gold is found in veins in the crust, with copper ore and native. Used in electronics, jewellery and coins. It is a good reflector of infrared radiation, so a thin film of gold is applied to the glass of skyscrapers to reduce internal heating from sunlight.

halogens    →   halogeni elementi

Halogens are the elements fluorine (F) chlorine (Cl), bromine (Br), iodine (I), and astatine (At). They are non-metals, and make up part of the 17 group in the periodic table. Compounds of these elements are called halogenides or halides.

The halogens all have a strong unpleasant odour and will burn flesh. They do not dissolve well in water. The five elements are strongly electronegative. They are oxidising agents, with fluorine being the strongest and astatine being the weakest. They react with most metals and many non-metals.

Halogens form molecules which consist of atoms covalently bonded. With increasing atomic weight there is a gradation in physical properties. For example: Fluorine is a pale green gas of low density. Chlorine is a greenish-yellow gas 1.892 times as dense as fluorine. Bromine is a deep reddish-brown liquid which is three times as dense as water. Iodine is a grayish-black crystalline solid with a metallic appearance. And astatine is a solid with properties which indicate that it is somewhat metallic in character.

methyl orange    →   metil oranž

Methyl orange is an acid-base indicator, in acid it turns red and in a base it turns yellow.

phosphorus    →   fosfor

Phosphorus was discovered by Hennig Brandt (Germany) in 1669. The origin of the name comes from the Greek word phosphoros meaning bringer of light. White phosphorus is white to yellow soft, waxy phosphorescent solid with acrid fumes. Toxic by inhalation, ingestion, or skin contact. Red phosphorus is powdery, non-flammable and non-toxic. Phosphorus is found most often in phosphate rock. Pure form is obtained by heating a mixture of phosphate rock, coke and silica to about 1450 °C. Used in the production of fertilizers and detergents. Some is used in fireworks, safety matches and incendiary weapons. Phosphorus is also important in the production of steels, phosphor bronze and many other products.

plutonium    →   plutonij

Plutonium was discovered by Glenn T. Seaborg, Edwin M. McMillan, J. W. Kennedy and A. C. Wahl (USA) in 1940. Named after the planet Pluto. It is silvery-white, extremely radioactive artificially produced metal. Reacts with oxygen and acids; resists alkalis. Attacked by steam. Highly toxic. Plutonium is found rarely in some uranium ores. Made by bombarding uranium with neutrons. Used in bombs and reactors. Small quantities are used in thermo-electric generators.

praseodymium    →   praseodimij

Praseodymium was discovered by Carl F. Auer von Welsbach (Austria) in 1885. The origin of the name comes from the Greek words prasios didymos meaning green twin. It is silvery white, moderately soft, malleable, ductile metal. Reacts slowly with oxygen. Reacts rapidly with water. Metal ignites and burns readily. Praseodymium is obtained from same salts as neodymium. Used with neodymium to make lenses for glass maker’s goggles since it filters out the yellow light present in glass blowing. Alloyed with magnesium creates a high-strength metal used in aircraft engines. Misch metal, used in the manufacture of pyrophoric alloys for cigarette lighters, contains about 5 % praseodymium metal. (Typically composition of misch metal are Ce:Nd:Pr:La:Other rare earth=50:18:6:22:4).

strontium    →   stroncij

Strontium was discovered by Sir Humphry Davy (England) in 1808. Named after the village of Strontian in Scotland. It is soft, malleable, silvery-yellow metal. Combustible in air, will react with water. Exposed surfaces form protective oxide film. Metal ignites and burns readily. Strontium is found in minerals celestite and strontianite. Used in flares and fireworks for crimson colour. Strontium-90 is a long lived highly radioactive fallout product of atomic-bomb explosions.

sulfur    →   sumpor

Sulfur has been known since ancient times. The origin of the name comes from the Sanskrit word sulvere meaning sulphur; also from the Latin word sulphurium meaning sulphur. It is pale yellow, odourless, brittle solid, which is insoluble in water but soluble in carbon disulfide. Sulfur is found in pure form and in ores like cinnabar, galena, sphalerite and stibnite. Pure form is obtained from underground deposits by the Frasch process. Used in matches, gunpowder, medicines, rubber and pesticides, dyes and insecticides. Also for making sulfuric acid (H₂SO₄).

superoxide    →   superoksid

Superoxides are binary compounds containing oxygen in the -½ oxidation state. Sodium superoxide (NaO₂) can be prepared with high oxygen pressures, whereas the superoxides of rubidium, potassium, and cesium can be prepared directly by combustion in air. These compounds are yellow to orange paramagnetic solids. Superoxide ion, O₂^-, has an unpaired electron, is not particularly stable, and spontaneously decomposes into peroxide over time.

They are strong oxidising agents that vigorously hydrolyze (react with water) to produce superoxide and oxygen gas.

TNT    →   TNT

TNT (2,4,6-trinitrotoluene) is a coluorless to pale yellow, odorless crystalline compound. It is an explosive used in military shells, bombs, and grenades, in industrial uses, and in underwater blasting.