CHEMISTRY GLOSSARY

blackbody    →   crno tijelo

In radiation physics, an ideal blackbody is a theoretical object that absorbs all the radiant energy falling upon it and emits it in the form of thermal radiation. Planck’s radiation law gives the power radiated by a unit area of blackbody, and the Stefan-Boltzman law expresses the total power radiated.

calorimetry    →   kalorimetrija

Calorimetry is a measurement of the amount of heat evolved or absorbed in a chemical reaction, change of state, or formation of a solution, or any other event that includes heat transfer.

carbon fibre    →   ugljično vlakno

Carbon fibres are threadlike strands of pure carbon that are strong and flexible. Carbon fibres can be bound in a plastic resin matrix to form a strong composite. It is light-weight and stronger than steel.

casein    →   kazein

Casein a protein substance found in milk in the form of calcium salt. It is used in industry of plastic masses and synthetic fibres or as an adhesive.

allotropic modification    →   alotropska modifikacija

Different substances of the same elementary system are called allotropes or allotropic modifications. In the case of oxygen, there are two allotropic modifications: "normal" dioxygen (O₂) and trioxygen (O₃) or ozone.

allotropy    →   alotropija

Allotropy (Gr. allos, other, and tropos, manner) is the phenomenon of an element existing in two or more physical forms in the same physical state. The difference between the forms involves either crystaline structure (white, red and black phosphorus), the number of atoms in the molecule of a gas (diatomic oxygen and triatomic ozone), or the molecular structure of a liquid (liquid helium an helium II).

In some cases, the allotropes are stable over a temperature range, with a definite transition point at which one changes into the other. For instance, tin has two allotropes: white (metallic) tin stable above 13.2 °C and grey (nonmetallic) tin stable below 13.2 °C. This form allotropy is called enantiotropy. Form of allotropy, in which there is no transition temperature at which the two are in equilibrium, is called monotropy.

Allotropy does not apply to the substance existing in different physical states as, for example, when ice melts and changes from solid ice to liquid water.

Allotropy is generally restricted to describing polymorphic behaviour in elements, while polymorphism may refer to any material having multiple crystal structures.

alpaca    →   alpaka

Alpaca (alpaka) or Nickel Silver is the generic name for any of a range of non-precious bright silvery-grey metal alloys, composed of copper, nickel and zinc. Despite its name it contains no real silver. It is also commonly called German Silver.

There are many different formulations of alloys which fall within the general term of Nickel Silver. All contain copper, nickel and zinc, while some formulations may additionally include antimony, tin, lead or cadmium. A representative formulation is 65 % copper, 18 % nickel, 17 % zinc. Nickel Silver is widely used for the commercial production of industrial components, housewares, flatware and cutlery, and as the metal substrate for silver-plated goods.

aluminate    →   aluminat

Aluminate is a salt formed when aluminium hydroxide or y-alumina is dissolved in solutions of strong bases, such as sodium hydroxide. Aluminates exist in solutions containing the aluminate ion, commonly written [Al(OH)₄]^-. In fact the ion probably is a complex hydrated ion and can be regarded as formed from a hydrated Al³⁺ ion by removal of four hydrogen ions:

Other aluminates and polyaluminates, such as [Al(OH)₆]^3- and [(HO)₃AlOAl(OH)₃]^2-, are also present.

aluminium    →   aluminij

Aluminium was discovered by Friedrich Wöhler (Germany) in 1827. The origin of the name comes from the Latin word alumen meaning alum. It is soft, lightweight, silvery-white metal. Exposed surfaces quickly form protective oxide coating. Metal reacts violently with oxidants. Third most abundant element in the earth’s crust. Aluminium is the most abundant metal to be found in the earth’s crust, but is never found free in nature. Aluminium is obtained by electrolysis from bauxite. Used for many purposes from airplanes to beverage cans. Too soft in its pure form so less than 1 % of silicon or iron is added, which hardens and strengthens it.

ampere    →   amper

Ampere (A) is the SI base unit of electric current.

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2×10^-7 newton per metre of length.