CHEMISTRY GLOSSARY

Volta, Alessandro    →   Volta, Alessandro

The Italian physicist Alessandro Giuseppe Antonio Anastasio Volta (1745-1827) was the inventor of the voltaic pile, the first electric battery (1800). In 1775 he invented the electrophorus, a device that, once electrically charged by having been rubbed, could transfer charge to other objects. Between 1776 and 1778, Volta discovered and isolated methane gas (CH₄). The electrical unit known as the volt was named in his honor.

voltaic pile    →   Voltin stup

Voltaic pile was the first device that produced a continuous electric current. The first piles constructed by the Italian physicist Alessandro Volta (1745-1827) in 1800 comprised alternating silver and zinc discs separated by cardboard soaked in brine. The pile can be stacked as high as you like, and each layer will increase the voltage by a fixed amount.

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.

voltameter    →   voltmetar

Voltammeter is an instrument for measuring voltages and amperages.

voltametry    →   voltametrija

Voltametry is a common name for a large group of instrumental techniques which are based on measuring the electric current formed by a continuous potential shifting on the electrodes.

volt    →   volt

Volt (V) is the SI derived unit of electric potential. One volt is the difference of potential between two points of an electric conductor when a current of 1 ampere flowing between those points dissipates a power of 1 watt. It was named after the Italian physicist Alessandro Volta (1745-1827).

galvanic celll    →   galvanski članak

Galvanic cell (voltaic cell) is a simple device with which chemical energy is converted into electrical energy. Galvanic cells consist of two separate compartments called half cells containing electrolyte solutions and electrodes that can be connected in a circuit. Two dissimilar metals (e.g., copper and zinc) are immersed in an electrolyte. If the metals are connected by an external circuit, one metal is reduced (i.e., gains electrons) while the other metal is oxidized (i.e., loses electrons).

In the example above, copper is reduced and zinc is oxidized. The difference in the oxidation potentials of the two metals provides the electric power of the cell.

A voltaic cell can be diagrammed using some simple symbols. In the diagram the electrodes are on the outer side of the diagram and a vertical line (|) is used to separate the electrode from the electrolyte solution found in the compartment. A double vertical line (||) is used to separate the cell compartments and is symbolic of the salt bridge. Usually in a diagram the species oxidized is written to the left of the double slash. Here is an example of the Daniell cell:

The names refer to the 18th-century Italian scientists Alessandro Volta (1745-1827) and Luigi Galvani (1737-1798).

voltaic cell    →   naponski članak

See Galvanic cell

accumulator    →   akumulator

Accumulator (secondary cell, storage battery) is a type of voltaic cell or battery that can be recharged by passing current through it from an external D.C. supply. The charging current reverses the chemical reactions in the cell. The common types are the lead-acid accumulator and the nickel-cadmium cell.

decomposition potential    →   potencijal razlaganja

Decomposition potential of some system is the smallest voltage which should be applied so that electrolysis occurs.