CHEMISTRY GLOSSARY

equivalent    →   ekvivalent

Equivalent (eq) is a unit for describing the amount of a chemical species. In contrast to the mole, the amount of a substance contained in one equivalent can vary from reaction to reaction.

first law of thermo-dynamics    →   prvi zakon termodinamike

First law of thermo-dynamics is: Energy can be neither created nor destroyed, but can cross from one shape to another.

herbicide    →   herbicid

Herbicide is any chemical compound used to kill pests that destroy agricultural production. Pesticide include herbicides (such as 2.4 D and Paraquat), which kill unwanted plants or weeds.

horse power    →   konjska snaga

Horse power is an obsolete non-SI of power introduced by James Watt in 1782 to allow describing the power of steam machinery. It was equal to the work effort of a horse needed to raise vertically 528 cubic feet of water to one metre in one minute (HP = 735.498750 W).

humidity    →   vlažnost

Humidity is a general term used to describe the amount of water vapor found in the atmosphere.

combustible    →   zapaljiv

The term combustible is often used to describe any material which will burn. However, conditions at which combustion will occur must be defined more accurately, for example a combustible liquid is 37.8 °C but below 93.3 °C. This allows a distinction to be made between combustible materials, which are fairly difficult to ignite, and flammable or highly flammable ones, which are far easier to ignite.

cyclic compound    →   ciklički spoj

Cyclic describing a compound that has a ring of atoms in its molecules. In homocyclic compounds all the atoms in the ring are of the same type, e.g. benzene (C₆H₆) and cyclohexane (C₆H₁₂). These two examples are also examples of carbocyclic compounds; i.e. the rings are made of carbon atoms. If different atoms occur in the ring, as in pyridine (C₅H₅N), the compound is said to be heterocyclic.

Dalton’s atomic theory    →   Daltonova atomska teorija

Dalton’s atomic theory is a theory of chemical combination, first stated by John Dalton in 1803. It involves the following postulates:

1. Elements consist of indivisible small particles (atoms).

2. All atoms of the same element are identical; different elements have different types of atom.

3. Atoms can neither be created nor destroyed.

4. ’Compound elements’ (i.e. compounds) are formed when atoms of different elements join in simple ratios to form ’compound atoms’ (i.e. molecules).

Dalton also proposed symbols for atoms of different elements (later replaced by the present notation using letters).

ion exchange    →   ionska izmjena

Ion exchange is a process involving the adsorption of one or several ionic species accompanied by the simultaneous desorption (displacement) of one or more other ionic species.

lecithin    →   lecitin

Lecithin is the popular name for a naturally occurring mixture of phospholipids (phosphatides) which is obtained from seeds (soybeans) and is used as a dispersing agent for fats. Lecithin is admitted by the EU as a food additive, designated by E number E322.