CHEMISTRY GLOSSARY

cerium    →   cerij

Cerium was discovered by Martin Heinrich Klaproth (Germany) and by Jöns Jacob Berzelius (Sweden) in 1803 and Wilhelm von Hisinger (Germany) in 1814. Named after the asteroid Ceres this discovered two years before the element. It is malleable, ductile, iron-grey metal. Tarnishes in air; reacts easily with water. Dissolves in acids; ignites when heated. Metal ignites and burns readily. Strong reductant. Cerium is most abundant rare earth metal. Found in many minerals like monazite sand [Ce(PO₄)]. Its oxides are used in the optics and glass-making industries. Its salts are used in the photography and textile industry. Used in high-intensity carbon lamps and as alloying agents in special metals.

chemical compound formula    →   formula kemijskog spoja

Chemical elements are represented by their symbols, and chemical compounds are represented by a group of symbols of those elements from which the compound is composed. That group of symbols, which shows which atoms and in which number relation they are present in certain compound is called a chemical compound formula.

In a formula chemical symbols show which element is present in a certain compound, and its index shows how much of that element there is in a certain compound. From sulphuric acid formula H₂SO₄ we can see that one molecule of sulphuric acid consists of two atoms of hydrogen, one atom of sulphur and four atoms of oxygen.

chiral centre    →   kiralno središte

Chiral centre in organic chemistry is most often an asymmetrically substituted carbon atom (C^*).

citrate    →   citrati

Citrate is a salt or ester of citric acid.

coal tar    →   ugljeni katran

Coal tar is a material obtained from the destructive distillation of coal in the production of coal gas. The crude tar contains a large number of organic compounds (e.g. benzene, naphthalene, methylbenzene, etc.), which can be separated by fractional distillation.

collagen    →   kolagen

Collagen is a polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin. Collagen is the primary organic constituent of bone, cartilage, and connective tissue (becomes gelatine through boiling).

condensed structural formulas    →   kondenzirane strukturne formule

Condensed structural formulas are shortened and easier layout of structural formulas of organic compounds (butane, CH₃(CH₂)₂CH₃).

conjugated base    →   konjugirana baza

Conjugated base is a particle which is left after a molecule of acid releases a proton.

chiral molecule    →   kiralne molekule

Chiral molecule is a molecule which cannot be superimposed on its mirror image. A common example is an organic molecule containing a carbon atom to which four different atoms or groups are attached. Such molecules exhibit optical activity, i.e., they rotate the plane of a polarised light beam.

chlorine    →   klor

Chlorine was discovered by Carl William Scheele (Sweden) in 1774. The origin of the name comes from the Greek word chloros meaning pale green. It is greenish-yellow, disagreeable gas with irritating odour. Gas is toxic and severe irritant by contact or inhalation. Never found in free form in nature. Commercial quantities of chlorine are produced by electrolysis of aqueous sodium chloride (NaCl) from seawater or brine from salt mines. Used in water purification, bleaches, acids and many, many other compounds such as chlorofluorocarbons (CFC).