CHEMISTRY GLOSSARY

complete ionic equation    →   potpuna ionska jednadžba

Complete ionic equation is a balanced equation that describes a reaction occurring in a solution, in which all strong electrolytes are written as dissociated ions.

complex    →   kompleks

Complex or coordination compound is formed when metal ion (central ion) reacts with molecules or ions which have free electron pairs (ligand). Metal ion and ligand are bonded with a polar covalent bond in which both electrons are given by the ligand.

condensational polymerisation    →   kondenzacijska polimerizacija

Condensational polymerisation is a reaction of polymerisation in which monomers together create a polymer by losing small molecules like water.

Born-Haber cycle    →   Born-Haberov kružni proces

Born-Haber cycle is a cycle of reactions used for calculating the lattice energies of ionic crystalline solids. For a compound MX, the lattice energy is the enthalpy of the reaction

The standard enthalpy of formation of the ionic solid is the enthalpy of the reaction

The cycle involves equating this enthalpy (which can be measured) to the sum of the enthalpies of a number of steps proceeding from the elements to the ionic solid. The steps are:

1) Atomization of the metal

2) Atomization of the nonmetal

3) Ionisation of the metal

This is obtained from the ionisation potential.

4) Ionisation of the nonmetal

This is electron affinity.

5) Formation of the ionic solids

Equation of the enthalpies gives

from which ΔH_L can be found.

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

cosmic rays    →   kozmičke zrake

Cosmic rays are high energy (10¹⁵ eV- 10¹⁷ eV) nuclear particles, electrons, and photons, originating mostly outside the solar system, which continually bombard the Earth’s atmosphere.

critical mass    →   kritična masa

Critical mass is the minimum mass of a fissionable material (²³⁵U or ²³⁹Pu) that will initiate an uncontrolled chain reaction as in an atomic bomb. The critical mass of pure ²³⁹Pu is about 4.5 kg, and of ²³⁵U about 15 kg.

disproportionation    →   disproporcioniranje

Disproportionation is a reaction in which the same molecule reduces and oxidates itself at the same time.

effervescence    →   pjenušanje

Effervescence is the formation of gas bubbles in a liquid by a chemical reaction. An example of effervescence is the release of carbon dioxide which bubbles as a gas from the liquid when limestone chips, which are composed of calcium carbonate, are added to dilute hydrochloric acid.

calorimeter    →   kalorimetar

Calorimeter is an instrument used to measure the energy absorbed or released in a chemical reaction. It also used in determining specific heat.