CHEMISTRY GLOSSARY

permanent hardness    →   stalna tvrdoća

Permanent hardness in water is hardness due to the presence of the chlorides, nitrates and sulphates of calcium and magnesium, which will not be precipitated by boiling. The lime scale can build up on the inside of the pipe restricting the flow of water or causing a blockage. This can happen in industry where hot water is used.

electrodialysis    →   elektrodijaliza

Electrodialysis is a procedure of dialysis accelerated with an electric field. Dialyser is divided into three sections. Solution flows through the middle section, between two semipermeable membranes alternately to positive ions and negative ions. An electrodes are placed in the neighbouring sections. Under the influence of electric field, positive ions will travel towards the cathode (the negative electrode), and negative ions towards the anode (the positive electrode), whereby travelling of ions through the membrane is accelerated. In this way, the feed water is separated into two streams: one of pure water and the other of more concentrated solution.

plain salt    →   jednostavna sol

Plain salt is a salt that contains only metal ions (or ammonium ions) and acid radical. It is created when all ions of hydrogen in an acid are replaced with ions of metal (or ammonium ions).

plastic sulphur    →   plastični sumpor

Plastic sulphur is the shape of sulphur which emerges when hot, liquid sulphur pours out in the water. It can be stretched in long fibres is unstable unstable. It easily solidifies.

polyvalent element    →   polivalentni elementi

Polyvalent element is a molecule which having more than one valence, for example oxygen is a divalent in H₂O, nitrogen is a trivalent in NH₃, carbon is a tetravalent in methane (CH₄).

primary alcohol    →   primarni alkohol

Primary alcohols are alcohols where the hydroxyl group is attached to a primary carbon atom. Thus, it has the general structure, RCH₂OH, where R is a hydrogen atom or an alkyl group.

electrolysis    →   elektroliza

Electrolysis is the decomposition of a substance as a result of passing an electric current between two electrodes immersed in the sample.

electrolytes    →   elektroliti

Electrolytes are substances which, when melted or dissolved in water, conduct electric current. By melting or dissolving they are dissociated into electrically charged particles (ions) which are able to conduct electric current. By passing of electric current the transfer of matter occurs. Positively charged particles (cations) travel towards the negative pole (the cathode) and negatively charged particles (the anions) travel towards the positive pole (the anode). Liquid metals, in which the conduction is by free electrons, are not usually regarded as electrolytes. Solid conductors of ions, as in the sodium-sulphur cell, are also known as electrolytes. Depending upon how it conducts electric current, matter can be divided into strong electrolytes, weak electrolytes and nonconductors.

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.

ether    →   eter

Ethers are organic compounds with a formula R-O-R, where R is not equal to H. They may be derived from alcohols by elimination of water, but the major method is catalytic hydration of olefins. They are volatile highly flammable compounds; when containing peroxides they can detonate on heating. The term ether is often used synonymously with diethyl ether.