CHEMISTRY GLOSSARY

fermion    →   fermioni

Fermion is any particle with spin equal to an odd multiple of 1/2. Fermion is a particle that obeys Fermi-Dirac statistics, e.g. electron, proton, neutron, muon, etc.

air stripping    →   zračni striping

Air stripping is a process for the removal of volatile organic contaminants from groundwater. The groundwater flows downward inside a tower filled with materials (the packing) over a large surface area. Air is introduced at the bottom of the tower and is forced upward past the falling water. The volatiles evaporate from the water and are collected in air filters or released to the atmosphere.

Allihn condenser    →   Allihnovo hladilo

Allihn condenser or bulb condenser consists of an outer water jacket and the inner glass tube with a series of spherical bubbles to maximize the thermal contact with the cooling water. It is named after its inventor, the German chemist Felix Richard Allihn (1854-1915).

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.

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.

fouling    →   obrastanje

1. Fouling is the deposition of insoluble materials, such as bacteria, colloids, oxides and water-borne debris, onto the surface of a reverse osmosis or ultrafiltration membrane. Fouling is associated with decreased flux rates and may also reduce the rejection rates of reverse osmosis membranes. Fouling also refers to the accumulation of normally inorganic deposits on heat exchanger tubing.

2. Fouling is an accumulation of marine organism deposits on a submerged metal surface.

geometrical optics    →   geometrijska optika

In most cases light can be described as an electromagnetic wave. Geometrical optics is an approximation in which the waves can be represented as straight-line rays. This approximation is valid if the light waves do not meet obstacles comparable in size to the wavelength of radiation.

ideal gas    →   idealni plin

Ideal gas is a gas in which there is complete absence of cohesive forces between the component molecules; the behaviour of such a gas can be predicted accurately by the ideal gas equation through all ranges of temperature and pressure. The concept is theoretical, since no actual gas meets the ideal requirement.

battery    →   baterija

Battery a device that converts chemical energy to electrical energy. The process underlying the operation of a battery involves a chemical reaction in which electrons are transferred from one chemical species to another. This process is carried out in two half-reactions, one that involves the loss of electrons and one that involves their gain. The battery is an electrochemical cell divided in two half-cells, and reaction proceeds when these are connected together by an electrically conducting pathway. The passage of electrons from one half-cell to the other corresponds to an electric current. Each half-cell contains an electrode in contact with the reacting species. The electrode which passes electrons into the circuit when battery discharges is called anode and is negative terminal. The electrode which receives electrons is called cathode, and is the battery’s positive terminal. The electrical circuit is completed by an electrolyte, an electrically conducting substance placed between the two electrodes which carriers a flow of charge between them. In wet cells, the electrolyte is a liquid containing dissolved ions, whose motion generates an electrical current; in dry cells the electrolyte is basely solid, for example, a solid with mobile ions or porous solid saturated with an ionic solution.

Biot-Savart law    →   Biot-Savartov zakon

The magnetic field B due to a current-carrying conductor can be determined by Biot-Savart law. The contribution to magnetic field set up at distance r by the current element IdL is given by expression:

where μ₀ is permeability constant. It plays a role in magnetic problems equivalent to the role of permittivity constant μ₀ in electrostatics problems. In order to obtain B, contributions of all current elements have to be integrated. In case of a long straight conductor, carrying current I, Biot-Savart law gives:

SI unit for magnetic field B is tesla (T).

Permaeability constant μ₀ has value 4π×10^-7 T m A^-1.