CHEMISTRY GLOSSARY
chromium → krom
Chromium was discovered by Louis-Nicholas Vauquelin (France) in 1797. The origin of the name comes from the Greek word chroma meaning colour. It is very hard, crystalline, steel-grey metal. The pure metal has a blue-white colour. It is hard, brittle and corrosion-resistant at normal temperatures. Hexavalent compounds toxic by skin contact. The most important chromium mineral is chromite [Fe,Mg(CrO4)]. Produced commercially by heating its ore in the presence of silicon or aluminium. Used to make stainless steel. It gives the colour to rubies and emeralds. Iron-nickel-chromium alloys in various percentages yield an incredible variety of the most important metals in modern technology.
Glauber’s salt → Glauberova sol
Glauber’s salt is sodium sulphate decahydrate (Na2SO4·10H2O). Loses water of hydration at 100 °C. Energy storage capacity is more than seven times that of water.
glyceride → glicerid
Glycerides are esters of glycerol (propane-1,2,3-triol) with fatty acids, widely distributed in nature. They are by a long-established custom subdivided into triglycerides, 1,2- or 1,3-diglycerides, and 1- or 2- monoglycerides, according to the number and positions of acyl groups.
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(symbol Cl) was defined as the weight of chlorine in grams per kilogram of seawater after the bromides and iodides had been replaced by chlorides.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
Clapeyron equation → Clapeyronova jednadžba
Clapeyron equation (also called the Clausius-Clapeyron equation) is a relation between pressure and temperature of two phases of a pure substance that are in equilibrium,
where ΔtrsS is the difference in entropy between the phases and ΔtrsV the corresponding difference in volume.
Citing this page:
Generalic, Eni. "Ledište." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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