CHEMISTRY GLOSSARY

barytes    →   barit

Barytes is an orthorhombic mineral, form barium sulphate, BaSO₄, the chief of barium. It is usually white but my also be yellow, grey or brown. Large deposits occur in Andalusia, Spain and in the USA.

chemical equation    →   kemijska jednadžba

Chemical equation is a way of denoting a chemical reaction using the symbol for the participating particles (atoms, molecules, ions, etc.); for example,

The single arrow is used for an irreversible reaction; double arrows are used for reversible reactions. When reactions involve different phases, it is usual to put the phase in brackets after the symbol.

The numbers a, b, c, and d, showing the relative numbers of molecules reacting, are called the stoichiometric coefficients. The convention is that stoichiometric coefficients are positive for reactants and negative for products. If the sum of the coefficients is zero, the equation is balanced.

copper    →   bakar

Copper has been known since ancient times. The origin of the name comes from the Latin word cuprum meaning the island of Cyprus famed for its copper mines. It is malleable, ductile, reddish-brown metal. Resistant to air and water. Exposed surfaces form greenish carbonate film. Pure copper occurs rarely in nature. Usually found in sulfides as in chalcopyrite (CuFeS₂), coveline (CuS), chalcosine (Cu₂S) or oxides like cuprite (Cu₂O). Most often used as an electrical conductor. Also used in the manufacture of water pipes. Its alloys are used in jewellery and for coins.

cracking    →   krekiranje

Cracking is the process whereby heavy molecules of petroleum or crude oil are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process).

dilute solution    →   razrijeđena otopina

Dilute solution contains a relatively low concentration of solute.

dipole    →   dipol

Dipole is a pair of separated opposite electric charges. Electric dipole is an assemblage of atoms or subatomic particles having equal electric charges of opposite sign separated by a finite distance. In the case of HCl, the electrons are attracted towards the more electronegative chlorine atom.

dipole molecule    →   dipolna molekula

Dipole molecules are created when mutual electronic pair at covalent bond is asymmetrical. If different atoms are bonded by a covalent bond, which can have different electron affinity, then the the atom with greater electron affinity will attract the electron pairs more strongly. In this way an asymmetrical distribution of negative charge appears in a molecule, so one part of the molecule becomes relatively negatively (the one closer to the electron pair) and the other becomes relatively positively charged.

isotope proportion    →   izotopni omjer

Isotope proportion is a number of atoms of each isotope in a sample of one element. It uses relative masses of isotopes to calculate a relative mass of one element.

molecular weight    →   molekularna masa

See Relative molecular mass

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.