CHEMISTRY GLOSSARY

non-polar solvent    →   nepolarno otapalo

Non-polar solvent is a liquid with non-polar molecules. It dissolves covalent compounds, non-water solvent.

nucleophile    →   nukleofil

Nucleophiles are negatively charged or bear a partial negative charge. Examples are lone pairs or a hydroxide ion.

oligomer    →   oligomer

Oligomer is a substance consisting of molecules of intermediate relative molecular mass (molecular weight), the structure of which essentially comprises the multiple repetitions of units derived, actually or conceptually, from molecules of low relative molecular mass. In contrast to a polymer, the properties of an oligomer can vary significantly with the removal of one or a few of its units.

oligosaccharide    →   oligosaharid

Oligosaccharides are carbohydrates containing from three to ten monosaccharide units, each joined to the next by a glycoside bond.

dissociation constant    →   konstanta disocijacije

Dissociation constant is a constant whose numerical value depends on the equilibrium between the undissociated and dissociated forms of a molecule. A higher value indicates greater dissociation.

The term dissociation is also applied to ionisation reactions of acids and bases in water. For example

which is often regarded as a straightforward dissociation into ions

The equilibrium constant of such a dissociation is called the acid dissociation constant or acidity constant, given by

The concentration of water [H₂O] can be taken as constant.

Similarly, for a base, the equilibrium

is also a dissociation; with the base dissociation constant or basicity constant, given by

K_a (K_b) is a measure of the strength of the acid (base).

electronegativity    →   elektronegativnost

Electronegativity is a parameter originally introduced by L. Pauling which describes, on a relative basis, the power of an atom to attract electrons. For example, in hydrogen chloride, the chlorine atom is more electronegative than the hydrogen and the molecule is polar, with a negative charge on the chlorine atom.

There are various ways of assigning values for the electronegativity of an element. Pauling electronegativities are based on bond dissociation energies using a scale in which fluorine, the most electronegative element, has the value 4 and francium, the lowest electronegative element, has the value 0.7.

osmometry    →   osmometrija

Osmometry is a determination of the average molecular weight of a dissolved substance from measurements of osmotic pressure.

oxonium ion    →   oksonijev ion

Oxonuim ion (H₃O⁺) is formed when a molecule of water binds with a proton.

polar solvent    →   polarno otapalo

Polar solvent is a liquid with polar molecules which dissolves polar compounds, because the charges on the endings of the solvent’s molecules attract the elements from ion crystals.

propagation    →   propagacija

Propagation is the step in a polymerization mechanism, where new monomer molecules are added to the growing polymer chain in the free radical process.