CHEMISTRY GLOSSARY

chemical change    →   kemijska promjena

Chemical change is a process which results in the production of one or more new materials. The system within which the process takes place is called a chemical system. A chemical change is also known as a chemical reaction, where one substance is converted into one or more different substances. When sodium and chlorine react to produce sodium chloride, a chemical reaction has taken place.

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.

free energy    →   slobodna energija

Free energy is an energy that is actually available to do useful work. A decrease in free energy accompanies any spontaneous process. Free energy does not change for systems that are at equilibrium.

Helmholz free energy    →   Helmholzova slobodna energija

Helmholz free energy (A) is a thermodynamic function defined by A = U - TS, where U is the internal energy, S the entropy, and T the thermodynamic temperature. For a reversible isothermal process ΔA represents the useful work available.

ionisation energy    →   energija ionizacije

Ionisation energy is the minimum energy required to remove an electron from an isolated atom or molecule (in its vibrational ground state) in the gaseous phase.

lattice energy    →   energija kristalne rešetke

Lattice energy is the energy per ion pair required to separate completely the ions in a crystal lattice at a temperature of absolute zero.

undispersed energy    →   nedispergirana energija

Undispersed is the energy is energy of a small defined system.

kinetic energy    →   kinetička energija

Kinetic energy (E_k) is associated with the state of motion of a body. It is a scalar property and defined to be

Kinetic energy is most clearly exhibited in gases, in which molecules have much greater freedom of motion than in liquids and solids.

vertical ionisation energy    →   vertikalna energija ionizacije

Vertical ionisation energy is the energy required to remove an electron from an atom, molecule, or ion in the gas phase without moving any nuclei. The vertical ionisation energy is greater than or equal to the adiabatic ionisation energy.

chemical potential    →   kemijski potencijal

For a mixture of substances, the chemical potential of constituent B (μ_B) is defined as the partial derivative of the Gibbs energy G with respect to the amount (number of moles) of B, with temperature, pressure, and amounts of all other constituents held constant.

Also called partial molar Gibbs energy. Components are in equilibrium if their chemical potentials are equal.