CHEMISTRY GLOSSARY

addition reactions    →   reakcije adicije

Addition reactions are normally occur with unsaturated compounds and involve the addition of one molecule (called the reactant) across the unsaturated bond (i.e. the double bond or the triple bond) of another molecule (called the substrate) to give a single product, formed by the combination of both reacting molecules.

For example, bromine adds across the double bond of ethene in an addition reaction to form dibromoethane.

electroorganic reaction    →   elektroorganske reakcije

Electroorganic reaction is an organic reaction produced in an electrolytic cell. Electroorganic reactions are used to synthesise compounds that are difficult to produce by conventional techniques. An example of an electroorganic reaction is Kolbe’s method of synthesising alkanes.

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)

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.

rate equation    →   jednadžba brzine reakcije

Rate equation is an equation that describes the dependence of reaction rate on concentrations of reacting species. It always has the form

where a and b are usually integral exponents.

reaction layer    →   reakcijski sloj

Reaction layer (in electrochemistry) is that layer of solution adjacent to an electrode within which a stationary distribution of electroactive species is established as the result of homogeneous reaction.

reaction mechanism    →   reakcijski mehanizam

Reaction mechanism is a list of all elementary reactions that occur in the course of an overall chemical reaction.

reaction order    →   red reakcije

Order of a reaction (n) is the sum of the exponents of the concentration terms in a rate equation.

Total order of a reaction is

reaction speed curve    →   krivulja brzine reakcije

Reaction speed curve is a graphic presentation of the reactant quantity change in dependence on time value.

second-order reactions    →   reakcije drugog reda

Second-order reaction is a reaction with a rate law that is proportional to either the concentration of a reactant squared, or the product of concentrations of two reactants.

For a general unimolecular reaction,

The reaction rate expression for a second order reaction is

If assumed that the concentration of reactant A is [A]_o at t=0 and [A] at time T, the variables in the rate equation and integrate can be separated. The integrated rate law for a second-order reaction can be easily shown to be