CHEMISTRY GLOSSARY

bag filter    →   vrećasti filtar

Bag filter is a unit within a mechanical system that bellows in a bag form when air flows through, cleaning the air by collecting particles of foreign matter. This system of filtering is rated the most efficient- in a range of 92 % to 95 %. Vacuum cleaner have a cloth filter bag.

Bag filter system is an economical method of liquid filtration consisting of the pressure vessel, restrainer basket and micron rated filter bag. Liquid flow is from the inside to the outside of the bag - dirt is trapped inside the bag.

barium    →   barij

Barium was discovered by Sir Humphry Davy (England) in 1808. The origin of the name comes from the Greek word barys meaning heavy. It is soft, slightly malleable, silvery-white metal. Attacked by air and water. Soluble compounds toxic by ingestion. Barium is found in barytine (BaSO₄) and witherite (BaCO₃), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure. Barite, or barium sulfate (BaSO₄), when ground is used as a filter for rubber, plastics and resins. It is insoluble in water and so is used in X-rays of the digestive system. Barium nitrate, Ba(NO₃)₂, burns brilliant green and is used in fireworks.

light year    →   svjetlosna godina

Light year (ly) is a unit of distance used in astronomy, defined as the distance light travels in one year in a vacuum (ly = 9.46052973·10¹⁵ m).

paramagnetism    →   paramagnetizam

Paramagnetism is a type of magnetism characterised by a positive magnetic susceptibility, so that the material becomes weakly magnetised in the direction of an external field. The magnetisation disappears when the field in removed.

purification    →   pročišćavanje

Purification is the physical or chemical process of removing contaminants from a compound. The physical processes may include sublimation, distillation, filtration, crystallisation, or extraction. The chemical processes may involve formation of a derivative, purification of the derivative and recovery of the original material in a pure form of the derivative.

barometer    →   barometar

Barometer is an instrument that measures atmospheric pressure. A mercury barometer is a closed tube filled with mercury inverted in a mercury reservoir. The height of the mercury column indicates atmospheric pressure (with 1 atm = 760 mm of mercury). An aneroid barometer consists of an evacuated container with a flexible wall. When atmospheric pressure changes, the wall flexes and moves a pointer which indicates the changing pressure on a scale.

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.

cathode    →   katoda

Cathode is a negative electrode of an electrolytic cell to which positively charged ions (cations) migrate when a current is passed as in electroplating baths.

In a primary or secondary cell (battery or accumulator) the cathode is the electrode that spontaneously becomes negative during discharge, and form which therefore electrons emerge.

In vacuum electronic devices electrons are emitted by the cathode and flow to the anode.

radiation    →   radijacija

The process of heat transfer which occurs through empty space and can also occur in matter, in the form of electro-magnetic (EM) waves, is called radiation or radiant heat. Whenever EM radiation is emitted and then absorbed, heat is transferred. This principle is used in microwave ovens, laser cutting, and RF hair removal.

refractive index    →   indeks loma

For a non-absorbing medium, refractive index (n) is the ratio of the velocity of electromagnetic radiation (light) in vacuum to the phase velocity of radiation of a specified frequency in the medium.