CHEMISTRY GLOSSARY

triple bond    →   trostruka veza

Triple bond. (≡) is a covalent bond that involves 3 bonding pairs. In the valence bond theory, one of the bonds in a triple bond is a sigma bond and the other two are pi bonds. For example, the central bond in acetylene is a triple bond: H-C≡C-H.

troposphere    →   troposfera

Troposphere is the lowest part of the earth’s atmosphere, extending to 10 km to 15 km above the surface. It is characterized by a decrease in temperature with increasing altitude. The exact height varies with latitude and season.

tryglyceride    →   triglicerid

Triglyceride is an ester of glycerol and three fatty acids. It is the main constituent of vegetable oil and animal fats. The fatty acids attached to the glycerol can be the same or different. Natural fatty acids found in plants and animals are typically composed only of even numbers of carbon atoms (usually from 16 to 20) due to the way they are bio-synthesized from acetyl CoA.

tryptophan    →   triptofan

Tryptophan is hydrophobic amino acids with aromatic side chain. Tryptophan is large aromatic residue that is normally found buried in the interior of a protein and is important for protein stability. Tryptophan has the largest side chain and is the least common amino acid in proteins. It has spectral properties that make it the best inherent probe for following protein folding and conformational changes associated with biochemical processes. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Trp, W
• IUPAC name: 2-amino-3-(1H-indol-3-yl)propanoic acid
• Molecular formula: C₁₁H₁₂N₂O₂
• Molecular weight: 204.23 g/mol

U-tube    →   U-cijev

U-tube filled with a sodium hydroxide is used for a cleaned and dried gas.

U-tube filled with a 1 mol dm^-3 aqueous potassium nitrate solution is used as a permanent salt bridge.

U-tube is a device used for water electrolysis, for laboratory hydrogen and oxygen obtaining.

U-tube manometer    →   U-manometar

U-tube manometer contains water or mercury in a U-shaped tube, and is usually used to measure gas pressure. One end of the U tube is exposed to the unknown pressure field (P) and the other end is connected to a reference pressure source (usually atmospheric pressure) (P_ref), shown in the schematic below.

If fluid C is the atmosphere, fluid B is the liquid in the U tube (e.g. water or mercury), and fluid A is a gas, then we can assume that ρB >> ρA, ρC. The pressure contributed by the weight of gas within the U tube can therefore be neglected. The gage pressure of the gas can be approximated by,

ultraviolet light    →   ultraljubičasto svjetlo

Ultraviolet light (UV light or UV radiation) is an electromagnetic radiation with a wavelength longer than that of x-rays, but shorter than that of visible light. Ultraviolet light can break some chemical bonds and cause cell damage.

unsaturated fat    →   nezasićena mast

Unsaturated fats, which include one or more unsaturated fatty acid, are liquid at room temperature (oil) and come from plant oils such as olive, peanut, corn, sunflower, safflower, and soybean. The fish oils may also be high in unsaturated fatty acids.

unsaturated fatty acid    →   nezasićena masna kiselina

Unsaturated fatty acid is a fatty acid whose carbon chain can absorb additional hydrogen atoms. Their carbon chain has one or more double or triple valence bond per molecule. The most important of these are:

vacuum filtration    →   vakuum filtracija

Vacuum filtration is a technique for separating a solid product from a liquid. The mixture of solid and liquid is poured through a filter paper in a Buchner funnel. The solid is trapped by the filter and the liquid is drawn through the funnel into the flask below, by a vacuum.