CHEMISTRY GLOSSARY

lutetium    →   lutecij

Lutetium was discovered by Georges Urbain (France) and independently by Carl Auer von Welsbach (Austria) in 1907. The origin of the name comes from the Greek word Lutetia meaning Paris. It is silvery-white and relatively stable in air, rare earth metal. Lutetium is found with ytterbium in gadolinite and xenotime. Stable lutetium nuclides can be used as catalysts in cracking, alkylation, hydrogenation, and polymerization.

salt bridge    →   solni most

Salt bridge is a permeable material soaked in a salt solution that allows ions to be transferred from one container to another. The salt solution remains unchanged during this transfer.

samarium    →   samarij

Samarium was discovered by Paul Emile Lecoq de Boisbaudran (France) in 1879. Named after the mineral samarskite. It is silvery rare earth metal. Stable in dry air. Oxide coating forms on surfaces exposed to moist air. Metal ignites and burns readily. Reacts with water. Samarium is found with other rare earths in monazite sand. It is used in the electronics and ceramics industries. It is easily magnetized and very difficult to demagnetise. This suggests important future applications in solid-state and superconductor technologies.

standard electrode potential    →   standardni elektrodni potencijal

Standard electrode potential (E°) (standard reduction potentials) are defined by measuring the potential relative to a standard hydrogen electrode using 1 mol solution at 25 °C. The convention is to designate the cell so that the oxidised form is written first. For example,

The e.m.f. of this cell is -0.76 V and the standard electrode potential of the Zn²+|Zn half cell is -0.76 V.

thulium    →   tulij

Thulium was discovered by Per Theodore Cleve (Sweden) in 1879. Named after Thule, an ancient name for Scandinavia. It is soft, malleable, ductile, silvery metal. Tarnishes in air. Reacts with water. Flammable dust. Thulium is found with other rare earths in the minerals gadolinite, euxenite, xenotime and monazite. Radioactive thulium is used to power portable X-ray machines, eliminating the need for electrical equipment.

Wohler’s synthesis    →   Wohlerova sinteza

Wöhler’s synthesis is a synthesis of urea performed by the German chemist Friedrich Wöhler (1800-1882) in 1828. He discovered that urea (CO(NH₂)₂) was formed when a solution of ammonium isocyanate (NH₄NCO) was evaporated. At the time it was believed that organic substances such as urea could only be made by living organisms, and its production from an inorganic compound was a notable discovery.

ytterbium    →   iterbij

Ytterbium was discovered by Jean de Marignac (France) in 1878. Named after Ytterby, a village in Sweden. It is silvery, lustrous, malleable and ductile metal. Oxidizes slowly in air. Reacts with water. Flammable dust. Ytterbium is found in minerals such as yttria, monazite, gadolinite and xenotime. Used in metallurgical and chemical experiments.

Schrotter apparatus for determination of CO2    →   Schrotterova aparatura za određivanje CO2

Schrötter decomposition apparatus (Schrötter's alkalimeter) is used to determining the carbonate content in samples of limestone, gypsum, dolomite, or baking powder by loss of weight. The apparatus is named after the Austrian chemist Anton Schrötter von Kristelli (1802-1875), who devised it in 1871. The size of the filled apparatus (apparatus is 16 cm high) is such that it weights less than 75 g, and can be placed on the pan of an analytical balance.

Procedure: Weigh about 0.5 g of the powdered carbonate sample and introduce it into the decomposition flask C. Pour into the drying tube A 2-3 mL of concentrated sulphuric acid (H₂SO₄), and to the dropping funnel B add about 10-15 mL of hydrochloric acid (w(HCl) = 15 %). Weigh the whole apparatus. Open the upper taps of both parts and allow the hydrochloric acid from B to run slowly down on to the powdered sample. The evolved CO₂ escapes through the strong sulphuric acid and is thus thoroughly dried. When further addition of acid produces no more evolution of CO₂, warm the apparatus up to 80 °C so as to expel the CO₂ from the solution. Connect the upper tap of the drying tube A to a water pump and draw a slow current of air through the apparatus until completely cool. Open the upper taps for a moment to equalize the internal and external pressure and weight the apparatus again. The weight loss is equal to the weight of carbon dioxide liberated from the carbonates.