CHEMISTRY GLOSSARY

average rate of reaction    →   prosječna brzina reakcije

Average rate of reaction is calculated in a way that a total change of reactants and products concentration is divided with time which is needed for reaction to end.

chemical balance    →   kemijska ravnoteža

Chemical balance is a degree of reversible reaction in a closed system, when the forward and backward reaction happen at same rates and their effects annul each other, while the concentration of reactants and products stays the same.

chemical equation equalization    →   izjednačavanje kemijske jednadžbe

Chemical equation equalization is determining values of stechiometric coefficients of reactants and products in a chemical equation in a way that the number of atoms of each element is equal before and after the reaction.

autocatalysis    →   autokataliza

Autocatalysis is a reaction in which its product can act as a catalyst. Oxalate oxidation with permanganate in an acid solution is a slow reaction

Mn²⁺-ions catalyse this reaction. When enough Mn²⁺-ions are created, the reaction occurs instantly.

biocapacity    →   biokapacitet

Biocapacity (or biological capacity) is the capacity of ecosystems to produce useful biological materials and to absorb carbon dioxide generated by humans, using current management schemes and extraction technologies. Useful biological materials are defined as those used by the human economy, hence what is considered useful can change from year to year. The biocapacity of an area is calculated by multiplying the actual physical area by the yield factor and the appropriate equivalence factor.

Yield factor is a factor that accounts for differences between countries in productivity of a given land type. Each country and each year has yield factors for cropland, grazing land, forest, and fisheries.

Equivalence factor is a productivity based scaling factor that converts a specific land type into a universal unit of biologically productive area, a global hectare (gha).

cement    →   cement

Cement is any various substances used for bonding or setting to a hard material. Portland cement is a mixture of calcium silicates and aluminates made by heating limestone (CaCO₃) with clay (containing aluminosilicates) in a kiln. The product is ground to a fine powder. When mixed with water it settles in a few hours and then hardens over a longer period of time due to the formation of hydrated aluminates and silicates.

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.

chemical reaction    →   kemijska reakcija

Chemical reaction is a change of chemical properties of substances which react with each other. By means of a chemical reaction new substances are created by bond breaking between atoms and molecules of reactants and their reuniting in a new way, thereby creating products. Chemical reactions can be shown by chemical equations.

chemical reaction equation    →   jednadžba kemijske reakcije

Chemical reactions are symbolically shown with chemical equations. On the left side of the equation we write formulas or substance symbols which enter the chemical reaction, reactants. On the right side formulas or substance symbols which emerge from the chemical reaction, products, are writen.

Each chemical reaction leads to an equilibrium which is moved more or less to one side (left or right). Because of that, in reversible reactions instead of = sign two opposite arrows are put

In order to write down certain chemical reaction equation all reactants and all products and their stechiometric proportions must be known. (See Chemical reaction balancing)

coal gas    →   ugljeni plin

Coal gas is a gas produced by the destructive distillation of coal, and contains approximately 50 % hydrogen, 35 % methane and 8 % carbon monoxide. The by-products of the production of coal gas are coal tar and coke.