CHEMISTRY GLOSSARY

second    →   sekunda

Second (s) is the SI base unit of time.

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels (F = 4, m_F = 0 to F = 3, m_F = 0) of the ground state of the caesium 133 atom.

secondary alcohol    →   sekundarni alkohol

Secondary alcohol is one in which the hydroxyl group (-OH) is attached to a secondary carbon atom (i.e. a carbon atom which has one hydrogen atom attached to it).

amines    →   amini

Amines are compounds formally derived from ammonia by replacing one, two, or three hydrogen atoms by hydrocarbyl groups, and having the general structures RNH₂ (primary amines), R₂NH (secondary amines), R₃N (tertiary amines). Examples are methylamine, CH₃NH₂; dimethylamine, CH₃NHCH₃; and trimethylamine, (CH₃)₃N.

Bragg angle    →   Braggov kut

Bragg angle (Θ) is the angle between an incident X-ray beam and a set of crystal planes for which the secondary radiation displays maximum intensity as a result of constructive interference. British physicist Sir William Henry Bragg and his son Sir William Lawrence Bragg developed a simple relation for scattering angles, now call Bragg’s law.

which relates the angle θ between a crystal plane and the diffracted X-ray beam, the wavelength λ of the x-rays, the crystal plane spacing d, and the diffraction order n (any integer).

The diffraction experiment as presently considered is intended to provide quantitative information on the lattice constant and shape characteristics of the unit cell.

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.

cgs system of units    →   cgs sustav jedinica

Cgs system of units is a system of units based upon the centimetre, gram, and second. The International System (SI) has supplanted the cgs system.

corrosion    →   korozija

Corrosion is a harmful and undesirable construction material consumption by the chemical activity of its surroundings. Corrosion concept refers to metal and nonmetal construction materials, but it is usually used for metals, Corrosion of metal, according to the mechanism process, is divided into chemical (corrosion in nonelectrolytes) and electrochemical (corrosion in electrolytes).

Chemical corrosion appears by direct action of molecule of some element or compound on metal, thus directly creating corrosion products.

Electrochemical corrosion of metals occurs in electrolytes, so reduction of metal atom into free cation appears which by secondary processes gives molecules of compound which are considered a corrosion product.

fluorescence    →   fluorescencija

Fluorescence is a luminescence phenomenon in which electron returns to it's ground state almost instantaneously (less than 10^-8 second), and in which emission from a luminescent substance ceases when the exciting source is removed. Fluorescence is characterized by radiation emission in all directions.

hertz    →   herc

Hertz (Hz) is the SI derived unit, with a special name, for frequency. The hertz is the frequency of a periodic phenomenon of which the period is one second (Hz = 1 s^-1). It was named after the German scientist Heinrich Hertza (1857 - 1894).

coulomb    →   kulon

Coulomb (C) is the SI unit of electric charge. It is equal to the charge transferred by a current of one ampere in one second (C = A s). The unit was named after the French physicist C. A. Coulomb (1736-1806).