CHEMISTRY GLOSSARY

bronze    →   bronca

Bronze is an alloy made primarily of copper and tin. It may contain as much as 25 % tin. Bronzes with 10 % or more tin are harder, stronger, and resistant to corrosion. As bronze weathers, a brown or green film forms on the surface. This film inhibits corrosion. Silicon or aluminium is often added to bronze to improve resistance to corrosion. Phosphorus, lead, zinc, and other metals may be added for special purposes. The alloy is hard and easily cast and is extensively used in bearings, valves and other machine parts.

Bronze was one of the first alloys developed by ancient metal workers. The Bronze Age occurred in Europe around 2200 to 700 BC. Bronze was used for weapons such as spearheads, swords, and knives. Since ancient times, bronze has been the most popular metal for casting statues and other art objects.

The term bronze has been adopted commercially for many copper-rich alloys that contain little or no tin but are similar in colour to bronze, including aluminium bronze, manganese bronze, and silicon bronze. Aluminium bronze is used to make tools and, because it will not spark when struck. Manganese bronze is actually a brass that contains manganese. It is often used to make ship propellers because it is strong and resists corrosion by sea water.

Buchner flask    →   Buchnerova tikvica

Büchner flask (also known as a vacuum flask, filter flask, side-arm flask or Kitasato flask) is a thick-walled Erlenmeyer flask with a side arm to which a vacuum can be applied.

equivalent weight    →   ekvivalentna masa

Equivalent weight of a substance participating in a neutralization reaction is that mass of substance (molecule, ion, or paired ion) that either reacts with or supplies 1 mol of hydrogen ions in that reaction.

Equivalent weight of a substance participating in an oxidation/reduction reaction is that weight which directly or indirectly produces or consumes 1 mol of electrons.

erosion    →   erozija

Erosion is a process by which the surface of the earth is constantly being worn away by wind action, fluvial processes, marine processes, and glacial processes.

Fermi level    →   Fermijev nivo

Fermi level is the highest energy of occupied states in a solid at zero temperature. The Fermi level in conductors lies in the conduction band, in insulators it lies in the valence band, and in semiconductors it falls in the gap between the conduction band and the valence band. It was named after the Italian physicst Enrico Fermi (1901 - 1954).

Bunsen burner    →   Bunsenov plamenik

Bunsen burner is a standard source of heat in the laboratory. German chemist Roberts Bunsen (1811-1899) improved the burner's design, which had been invented by Faraday, to aid his endeavors in spectroscopy. The Bunsen burner has a vertical metal tube through which a fine jet of fuel gas is directed. Air is drawn in through airholes near the base of the tube and the mixture is ignited and burns at the tube’s upper opening. The flow of this air is controlled by an adjustable collar on the side of the metal tube. When the whole is closed a yellow safety flame is displayed. Where as when the whole is open it displays a power dull blue flame with a faint blue outer flame with a vibrant blue core used u for combustion and hearting. The flame can reach temperatures of 1 500 °C.

cadmium    →   kadmij

Cadmium was discovered by Friedrich Strohmeyer (Germany) in 1817. The origin of the name comes from the Latin word cadmia meaning calamine (zinc carbonate, ZnCO₃), or from the Greek word kadmeia with the same meaning. It is soft, malleable, blue-white metal. Tarnishes in air, soluble in acids, insoluble in alkalis. Boiling cadmium gives off a weird, yellow-colored vapour that is poisonous. Cadmium can cause a variety of health problems, including kidney failure and high blood pressure. Cadmium is obtained as a by product of zinc refining. The mayor use of cadmium is in electroplating of steel to protect it from corrosion. Also used to make nickel-cadmium batteries. The ability of cadmium to adsorb neutrons has made it of great importance in the design of nuclear reactors. Its compounds are found in paint pigments and a wide variety of intense colours.

fire-damp    →   plin praskavac

Fire-damp is a mixture of two volume parts of hydrogen and one volume part of oxygen which, if set on fire, strongly explodes, the flame giving of a very high temperature (2 000 °C).

freezing    →   smrzavanje

Freezing is the change of a liquid into a solid state as the temperature decreases. For water, the freezing point is 0 °C (or 273.16 K).

gel    →   gel

Gels are colloids in which both dispersed and continuous phases have a three-dimensional network throughout the material, so that it forms a jelly-like mass (e.g. gelatine). One component may sometimes be removed to leave a rigid gel (e.g. heating silica gel).