CHEMISTRY GLOSSARY

three way safety bulb    →   propipeta

Three way safety bulb (pipette filler bulb) is used for pipeting. The attachment is placed over the mouth of the pipet. Squeeze the air valve (A) and the bulb simultaneously to empty the bulb of air. Place the tip of the pipet below the solution's surface in the beaker. Gradually squeeze the suction valve (S) to draw liquid into the pipet. If the level of the solution is not high enough, squeeze the air valve (A) and the bulb again to expel the air from the bulb. Draw up more liquid by squeezing the suction valve (S). When the liquid is above the specified volume, stop squeezing the suction valve (S). Do not remove the bulb from the pipet. Do not allow liquid to enter the pipet bulb.

threonine    →   treonin

Threonine is neutral amino acids with polar side chains. It differs from serine by having a methyl substituent in place of one of the hydrogens on the β carbon. Threonine is a site of phosphorylation and glycosylation which is important for enzyme regulation and cell signaling. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Thr, T
• IUPAC name: 2-amino-3-hydroxybutanoic acid
• Molecular formula: C₄H₉NO₃
• Molecular weight: 119.12 g/mol

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.

tin    →   kositar

Tin has been known since ancient times. The origin of the name comes from the Latin word stannum meaning tin. It is silvery-white, soft, malleable and ductile metal. Exposed surfaces form oxide film. Resists oxygen and water. Dissolves in acids and bases. Organic tin compounds may be highly toxic. Tin is principally found in the ore cassiterite (SnO₂) and stannine (Cu₂FeSnS₄). Used as a coating for steel cans since it is non-toxic and non-corrosive. Also in solder (33 %Sn:67 %Pb), bronze (20 %Sn:80 %Cu) and pewter. Stannous fluoride (SnF₂), a compound of tin and fluorine is used in some toothpaste.

titanium    →   titanij

Titanium was discovered by William Gregor (England) in 1791. Named after the Titans, the sons of the Earth goddess in Greek mythology. It is shiny, dark-grey metal. Powdered form burns in air. Exposed surfaces form oxide coating. It can be highly polished and is relatively immune to tarnishing. Unreactive with alkali and most acids. Titanium usually occurs in the minerals ilmenite (FeTiO₃), rutile (TiO₂) and iron ores. Pure metal produced by heating TiO₂ with C and Cl₂ to produce TiCl₄ then heated with Mg gas in Ar atmosphere. Since it is strong and resists acids it is used in many alloys. Titanium dioxide (TiO₂), a white pigment that covers surfaces very well, is used in paint, rubber, paper and many others.

titar    →   titar

Titar (T) is a mass of titrated matter which is equivalent to 1 cm³ of solution. It is shown as T = 2.356 mg HCl / 1.0 cm³ NaOH, 0.1000 moldm^-3, and it is usually shown in a table form. If the concentration of used standard solution (c) differs from one outlined in the table data (c₀), the factor of correction (f) is induced

Titar is usually used in industrial operational laboratories where from titar tables mass or percentage of the ingredient in question is directly read.

titration curve    →   titracijska krivulja

Titration curve is a graphic representation of the amount of a species present vs. volume of solution added during a titration. A titration curve has a characteristic sigmoid curve. The inflection point in the titration curve marks the end-point of the titration. Blue line is the first derivative of the titration curve.

TNT    →   TNT

TNT (2,4,6-trinitrotoluene) is a coluorless to pale yellow, odorless crystalline compound. It is an explosive used in military shells, bombs, and grenades, in industrial uses, and in underwater blasting.

torr    →   tor

Torr is obsolete unit of pressure. It is equal to the pressure exerted by a column of mercury one milimetre high, measured at 0 °C. The unit was named after the Italian physicist Evangelista Torricelli (1852-1908).

1 torr = 1 mmHg (0 °C)

760 torr = 1 atm

1 torr = (101 325/760) Pa

Torricelli, Evangelista    →   Torricelli, Evangelista

Evangelista Torricelli (1852-1908) is Italian physicist and mathematician. He became the first scientist to create a sustained vacuum and to discover the principle of a barometer. He filled a tube three feet long, and hermetically closed at one end, with mercury and set it vertically with the open end in a basin of mercury, taking care that no air-bubbles should get into the tube. The column of mercury invariably fell to about twenty-eight inches, leaving an empty space above its level. He discovered that the variation of the height of the mercury from day to day was caused by changes in the atmospheric pressure. He also constructed a number of large objectives and small, short focus, simple microscopes.