CHEMISTRY GLOSSARY

vitamin    →   vitamin

The name vitamin is obtained from vital amines as it was originally thought that these substances were all amines. This is now known not to be true as vitamins have a range of structures. The body requires a small amout of vitamins, but any deficiency leads to metabolic and physical disorders.

VSEPR    →   VSEPR

Valence shell electron pair repulsion theory (VSEPR) is a model that explains the shapes of molecules by assuming that electron pairs arrange themselves around atoms in a way that minimizes electron-electron repulsions.

hydration    →   hidratacija

Hydration is addition of water or the elements of water (i.e. H and OH) to a molecular entity. The term is also used in a more restricted sense for the process:

hydrogen bond    →   vodikova veza

Hydrogen is a bond formed by a hydrogen atom to an electronegative atom, and is denoted by dashed lines H-X---H-B. A hydrogen atom covalently bound to an oxygen (electronegative atom) has a significant positive charge and can form a weak bond to another electronegative atom.

hydrolysis    →   hidroliza

Hydrolysis is a chemical reaction in which water reacts with another substance to form two or more new substances. This involves ionisation of the water molecule, as well as splitting of the compound hydrolysed, e.g.

Examples are conversion of starch to glucose by water in the presence of suitable catalysts and a reaction of the ions of a dissolved salt to form various products, such as acids, complex ions, etc.

ideal solution    →   idealna otopina

Ideal solution is a solution in which solvent-solvent and solvent-solute interactions are identical, so that properties such as volume and enthalpy are exactly additive. Ideal solutions follow Raoult’s law, which states that the vapour pressure p_i of component i is p_i = x_i p_i^*, where x_i is the mole fraction of component i and p_i^* the vapour pressure of the pure substance i.

ion exchanger    →   ionski izmjenjivač

Ion-exchanger is a solid or liquid material containing ions that are exchangeable with other ions with a like charge that are present in a solution in which the material is insoluble. Ion-exchange resins consist of various copolymers having a cross-linked three-dimensional structure to which ionic groups have been attached.

wavefunction    →   valna funkcija

Wavefunction (Ψ) is a mathematical function that gives the amplitude of a wave as a function of position (and sometimes as a function of time and/or electron spin). Wavefunctions are used in chemistry to represent the behaviour of electrons bound in atoms or molecules.

weak electrolyte    →   slabi elektrolit

Weak electrolytes are those electrolytes which in water solutions dissociate only partially, giving ions and which are in equilibrium with undissociated molecules. Their water solutions conduct electric current weakly. For example, acetic acid partially dissociates into acetate ions and hydrogen ions, so that an acetic acid solution contains both molecules and ions.

X-ray diffraction pattern    →   rendgenski difrakcijski uzorci

X-ray diffraction pattern is an interference pattern created by x-rays as they pass through a solid material. Studying X-ray diffraction patterns gives detailed information on the three-dimensional structure of crystals, surfaces, and atoms.