CHEMISTRY GLOSSARY

carbolineum    →   karbolineum

Carbolineum is a mixture of ingredients of pit coal tar with the boiling point above 270 °C, red-brown oil with tar smell. It is a wood preservative.

coal    →   ugljen

Coal is a black or brownish-black, combustible sedimentary rock, with 30 % (lignite) to 98 % (anthracite) carbon by weight, mixed with various amounts of water and small amounts of sulfur and nitrogen compounds. It is formed from plant matter that decayed in swamps and bogs that has been compressed and altered by geological processes over millions of years. Coal is primarily used as a fuel.

Dalton, John    →   Dalton, John

Dalton, John (1766-1844) British chemist and physicist. In 1801 he formulated his law of partial pressures (Dalton’s law), but he is best remembered for Dalton’s atomic theory, which he announced in 1803. Dalton also studied colour blindness (a condition, once called Daltonism, that he shared with his brother).

catalytic cracking    →   katalitčko krekiranje

Catalytic cracking is a petroleum refining process in which heavy-molecular weight hydrocarbons are broken up into light hydrocarbon molecules by the application of heat and pressure in the presence of a catalyst.

copper    →   bakar

Copper has been known since ancient times. The origin of the name comes from the Latin word cuprum meaning the island of Cyprus famed for its copper mines. It is malleable, ductile, reddish-brown metal. Resistant to air and water. Exposed surfaces form greenish carbonate film. Pure copper occurs rarely in nature. Usually found in sulfides as in chalcopyrite (CuFeS₂), coveline (CuS), chalcosine (Cu₂S) or oxides like cuprite (Cu₂O). Most often used as an electrical conductor. Also used in the manufacture of water pipes. Its alloys are used in jewellery and for coins.

electromagnetic wave    →   elektromagnetski val

All matter absorbs and emits radiation covering a broad band of frequencies and wavelengths. Thus electromagnetic radiation has the velocity of light (2.998×10⁸ ms^-1) and arises from the vibrating electric charges in atoms and bonds. The range of wavelengths, also known as the electromagnetic spectrum, is shown below:

fusion    →   fuzija

Fusion is nuclear reaction in which atomic nuclei are brought together into a larger nucleus, releasing a large amount of energy. It is also used in the production of hydrogen bombs.

irreversible process    →   ireverzibilni proces

If a system is taken from one state to another but cannot be brought back to the same initial state, then the process is called irreversible. Some examples are free expansion of a gas; dissipation of energy due to friction, or the mixing of two gases or liquids etc.

chlorinity    →   klorinitet

Originally chlorinity (symbol Cl) was defined as the weight of chlorine in grams per kilogram of seawater after the bromides and iodides had been replaced by chlorides. To make the definition independent of atomic weights, chlorinity is now defined as 0.3285233 times the weight of silver equivalent to all the halides.

The Mohr-Knudsen titration method served oceanographers for more than 60 years to determine salinity from chlorinity. This modification of the Mohr method uses special volumetric glassware calibrated directly in chlorinity units. The Mohr method uses potassium chromate (K₂CrO₄) as an indicator in the titration of chloride ions chloride (plus a small amount of bromide and iodide) with a silver nitrate (AgNO₃) standard solution.

The other halides present are similarly precipitated.

A problem in the Mohr titration was that silver nitrate is not well suited for a primary standard. The Danish physicist Martin Knudsen (1871-1949) suggested that a standard seawater (Eau de mer Normale or Copenhagen Normal Water) be created and distributed to oceanographic laboratories throughout the world. This water was then used to standardize the silver nitrate solutions. In this way all chlorinity determinations were referred to one and the same standard which gave great internal consistency.

The relationship between chlorinity Cl and salinity S as set forth in Knudsen's tables is

In 1962, however, a better expression for the relationship between total dissolved salts and chlorinity was found to be

cracking    →   krekiranje

Cracking is the process whereby heavy molecules of petroleum or crude oil are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process).