CHEMISTRY GLOSSARY

rare earth elements    →   elementi rijetkih zemalja

Rare earth elements (metals) are the elements scandium (Sc), yttrium (Y), and the lanthanides (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). These elements got their name from the fact that chemists first isolated them in their oxide forms. These oxides somewhat resemble calcium, magnesium and aluminium oxides, sometimes called common earths. Do you want to know more?

thermodynamic equilibrium    →   termodinmička ravnoteža

Thermodynamic equilibrium is a system equilibrium in which energy that it gains from its surroundings is exactly balanced by the energy that it loses, no matter how much time is allowed to pass.

thermoplastic    →   termoplastika

Thermoplastic is ap lastic polymer material that can be repeatedly softened through heating and hardened again by cooling. Examples are PVCor polistiren, which when heated, softens to enable moulding and welding, but on cooling hardens. If the finished product is not correct, the material can be heated and manipulated again.

Rayleigh number    →   Rayleighova značajka

Rayleigh number (Ra) is a dimensionless quantity used in fluid mechanics, defined by

where l is length, g is acceleration of gravity, α is cubic expansion coefficient, T is temperature, ρ is density, η is viscosity, and a is thermal diffusivity.

redox potential    →   redoks potencijal

Redox potential is the potential of a reversible oxidation-reduction electrode measured with respect to a reference electrode, corrected to the hydrogen electrode, in a given electrolyte.

redox reaction    →   redoks-reakcija

Redox reaction is an oxidation-reduction reaction is a reaction in which one or more electrons are transferred. When an atom, ion, or molecule loses one or more electrons, it is oxidised. When an atom, ion, or molecule gains one or more electrons, it is reduced.

refractometer    →   refraktometar

Refractometer is an optical device used from measurement of refractive index. A refractometer takes advantage of the fact that light bends as it passes through different materials. It can be used to measure the salinity of water or the amount of sugar in fresh grapes. Refractometers are available with or without automatic temperature compensation (ATC).

When using a conventional saltwater refractometer, a sample is placed on an optical prism in the sample window. As light shines through the sample, it is bent according to the salinity of the water, and casts a shadow on the scale that is visible through the eyepiece. Salinity is read directly through the eyepiece.

thermostat    →   termostat

Thermostat is a device which controls the heating or cooling of a substance, by turning the machinery on or off, in order to maintain a constant temperature.

thio    →   tio

Thio- is a prefix that means, replace oxygen with sulphur. For example, a sulphate ion is SO₄^2-; a thiosulphate ion is S2O₃^2-. A cyanate ion is OCN^-; a thiocyanate ion is SCN^-.

TISAB    →   TISAB

TISAB (Total Ionic Strength Adjustment Buffer) is a buffer solution which maintains a constant activity of an analyte in solution.