CHEMISTRY GLOSSARY

electroanalytical chemistry    →   elektroanalitička kemija

Electroanalytical chemistry chemistry is the application of electrochemical cells and electrochemical techniques for chemical analysis. The analyte is dissolved in the electrolyte of the cell, and one can perform either qualitative analysis (determination of the type of constituents present) or quantitative analysis (determination of the amount of a given constituent).

Butler-Volmer equation    →   Butler-Volmerova jednadžba

Butler-Volmer equation is an activation controlled reaction, the one for which the rate of reaction is controlled solely by the rate of the electrochemical charge transfer process, which is in turn an activation-controlled process. This gives rise to kinetics that are described by the Butler-Volmer equation:

where i_o is exchange current density, η is overpotential (η = E - E_o), n is number of electrons, α_A is anodic transfer coefficient, and α_C is cathodic transfer coefficient

cell potential    →   potencijal članka

Cell potential (E) is difference between anode and cathode potential. If the cell potential is positive, then the reaction is spontaneous.

corrosion    →   korozija

Corrosion is a harmful and undesirable construction material consumption by the chemical activity of its surroundings. Corrosion concept refers to metal and nonmetal construction materials, but it is usually used for metals, Corrosion of metal, according to the mechanism process, is divided into chemical (corrosion in nonelectrolytes) and electrochemical (corrosion in electrolytes).

Chemical corrosion appears by direct action of molecule of some element or compound on metal, thus directly creating corrosion products.

Electrochemical corrosion of metals occurs in electrolytes, so reduction of metal atom into free cation appears which by secondary processes gives molecules of compound which are considered a corrosion product.

galvanostat    →   galvanostat

Galvanostat is an electronic instrument that controls the current through an electrochemical cell at a preset value, as long as the needed cell voltage and current do not exceed the compliance limits of the galvanostat.

negative pole    →   negativan pol

Negative pole is that half-cell in electrochemical cell that has the most negative electrode potential.

cyclic voltammetry    →   ciklička voltametrija

Cyclic voltammetry (CV) is an electrochemical measuring technique used for the determination of the kinetics and mechanism of electrode reactions. The potential of the working electrode is controlled (typically with a potentiostat) and the current flowing through the electrode is measured. It is a linear-weep voltammetry with the scan continued in the reverse direction at the end of the first scan. This cycle can be repeated a number of times, and is used for corrosion studies.

positive pole    →   pozitivni pol

Positive pole is that half-cell in the electrochemical cell which has the most positive electrode potential.

electrolysis    →   elektroliza

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

electrolytic cell    →   elektrolitska ćelija

Electrolytic cell is an electrochemical cell that converts electrical energy into chemical energy. The chemical reactions do not occur spontaneously at the electrodes when they are connected through an external circuit. The reaction must be forced by applying an external electric current. It is used to store electrical energy in chemical form (rechargeable battery). It is also used to decompose or produce (synthesise) new chemicals by the application of electrical power. This process is called electrolysis, e.g., water can be decomposed into hydrogen gas and oxygen gas. The free energy change of the overall cell reaction is positive.