CHEMISTRY GLOSSARY

toxicant    →   toksikant

Toxicant is a comparatively rarely-used term which describes any material which is potentially toxic.

toxicology    →   toksikologija

Toxicology is a science which studies all kinds of poisons and their effects on live organisms.

lactic acid    →   mliječna kiselina

Lactic acid is an acid produced as a result of anaerobic respiration in muscles and red blood cells, i.e. when glycogen is used as an energy source for respiration rather than oxygen. After production, it is converted back to glycogen in the liver. The build up of large amounts of lactic acid in the blood can lead to stress and toxic effects. High levels are usually a result of sustained, excessive exercise.

lead    →   olovo

Lead has been known since ancient times. The origin of the name comes from the Latin word plumbum meaning liquid silver. It is very soft, highly malleable and ductile, blue-white shiny metal. Tarnishes in moist air; stable in oxygen and water. Dissolves in nitric acid. Compounds toxic by inhalation or ingestion. Danger of cumulative effects. Lead is found most often in ores called galena or lead sulfide (PbS). Used in solder, shielding against radiation and in batteries.

lead-acid battery    →   olovni akumulator

Lead-acid battery is a electrical storage device that uses a reversible chemical reaction to store energy. It was invented in 1859 by French physicist Gaston Planté. Lead-acid batteries are composed of a lead(IV) oxide cathode, a sponge metallic lead anode and a sulphuric acid solution electrolyte.

In charging, the electrical energy supplied to the battery is changed to chemical energy and stored. The chemical reaction during recharge is normally written:

In discharging, the chemical energy stored in the battery is changed to electrical energy. During discharge, lead sulfate (PbSO4) is formed on both the positive and negative plates. The chemical reaction during discharge is normally written:

Lead acid batteries are low cost, robust, tolerant to abuse, tried and tested. For higher power applications with intermittent loads however, they are generally too big and heavy and they suffer from a shorter cycle life.

mercury    →   živa

Mercury has been known since ancient times. The origin of the name comes from the Latin word hydrargyrum meaning liquid silver. It is heavy, silver-white metal, liquid at ordinary temperatures. Stable in air and water. Unreactive with alkalis and most acids. Gives off poisonous vapour. Chronic cumulative effects. Mercury only rarely occurs free in nature. The chief ore is cinnabar or mercury sulfide (HgS). Used in thermometers, barometers and batteries. Also used in electrical switches and mercury-vapour lighting products.

osmium    →   osmij

Osmium was discovered by Smithson Tennant (England) in 1803. The origin of the name comes from the Greek word osme meaning smell. It is hard fine black powder or hard, lustrous, blue-white metal. Unaffected by air, water and acids. Characteristic acrid, chlorine like odour due to tetroxide compound. Osmium tetroxide highly toxic. Osmium is obtained from the same ores as platinum. Used to tip gold pen points, instrument pivots, to make electric light filaments. Used for high temperature alloys and pressure bearings. Very hard and resists corrosion better than any other.

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.

polonium    →   polonij

Polonium was discovered by Marie Curie (Poland) in 1898. Named for Poland, native country of Marie Curie. It is silvery-grey, extremely rare, radioactive metal. Soluble in dilute acids. Highly toxic. Severe radiotoxicity. Carcinogen. Polonium occurs in pitchblende. Produced by bombarding bismuth with neutrons. Used in industrial equipment that eliminates static electricity caused by such processes as rolling paper, wire and sheet metal.

polychlorinated biphenyls    →   poliklorirani bifenili

Polychlorinated biphenyls (PCB) are poisonous and carcinogenic compounds. They are pollutants of both live and inanimate environment, and they are used as insulation and refrigerating materials in transformers and condensers.