CHEMISTRY GLOSSARY

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.

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)

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 raw material    →   kemijske sirovine

Chemical raw material are petroleum fractions used for obtaining organic chemicals, those are mostly refined gas and petroleum or fraction parts of petrol.

heat of reaction    →   toplina kemijske reakcije

Heat of reaction or enthalpy of reaction is the heat evolved or absorbed as a result of the complete chemical reaction of molar amounts of the reactants.

Navier-Stokes equations    →   Navier-Stokesove jednadžbe

Navier-Stokes equations are a set of complex equations for the motion of a viscous fluid subject to external forces.

Arrhenius equation    →   Arheniusova jednadžba

In 1889, Svante Arrhenius explained the variation of rate constants with temperature for several elementary reactions using the relationship

where the rate constant k is the total frequency of collisions between reaction molecules A times the fraction of collisions exp(-E_a/RT) that have an energy that exceeds a threshold activation energy E_a at a temperature of T (in kelvin). R is the universal gas constant.

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 symbols    →   kemijski simboli

Chemical symbols are a derived way of showing elements in a formula or equation. Each symbol represents one atom and it usually consists of the first two letters of the Greek or Latin name of the element.

van’t Hoff equation    →   van Hoffova jednadžba

Van’t Hoff equation is the equation expressing the temperature dependence on the equilibrium constant K of a chemical reaction:

where Δ_rH° is the standard enthalpy of reaction, R the molar gas constant, and T the temperature.