CHEMISTRY GLOSSARY
water softening → omekšavanje vode
Water softening is a process in which calcium and magnesium ions are removed from water. It is usually done by ion exchanger which exchanges removed ions with sodium ones.
gamma radiation → gama-zračenje
Gamma radiation is electromagnetic radiation of extremely short wavelength. Gamma radiation ranges in energy from about 10-15 J to 10-10 J (10 keV to 10 MeV) (wavelength less than about 1 pm). Gamma rays are emitted by excited atomic nuclei during the process of passing to a lower excitation state.
Gamma rays are extremely penetrating and are absorbed by dense materials like lead and uranium. Exposure to gamma radiation may be lethal.
gas liquefying → ukapljivanje plinova
In order to achieve transition of a gas into liquid state it is necessary to lower its temperature, or decrease its volume, or increase its pressure. Above the critical temperature it is impossible to liquefy a gas. When liquefying a gas by Linde’s procedure, dampening or Joule-Thomson’s effect is used. First, the compressed air from the compressor is cooled with cooling water, the cooled air expands at a lower pressure in the dampening valve at which it cooled. The cooled air now returns to the compressor, cooling down the expanding air. By repeating this process the air is cooled enough to transit to the liquid state.
glucose → glukoza
Glucose (grape sugar, blood sugar), C6H12O6, is an aldohexose (a monosaccharide sugar having six carbon atoms and an aldehyde group). An older common name for glucose is dextrose, after its dextrorotatory property of rotating plane polarized light to the right. Glucose in free (in sweet fruits and honey) or combined form (sucrose, starch, cellulose, glycogen) is is probably the most abundant organic compound in nature. During the photosynthesis process, plants use energy from the sun, water from the soil and carbon dioxide gas from the air to make glucose. In cellular respiration, glucose is ultimately broken down to yield carbon dioxide and water, and the energy from this process is stored as ATP molecules (36 molecules of ATP across all processes).
Naturally occurring glucose is D isomers (OH group on the stereogenic carbon farthest from the aldehyde group, C-5, is to the right in the Fischer projection). Although often displayed as an open chain structure, glucose and most common sugars exist as ring structures. In the α form, the hydroxyl group attached to C-1 and the CH2OH attached to C-5 are located on opposite sides of the ring. β-glucose has these two groups on the same side of the ring. The full names for these two anomers of glucose are α-D-glucopyranose and β-D-glucopyranose.
graphite → grafit
Graphite is an allotrope of carbon. The atoms are arranged in layers as a series of flat, hexagonal rings. Graphite is a good conductor of heat and electricity. The layers cleave easily, making graphite useful as a solid lubricant. A process to make pure synthetic graphite was invented by the American chemist Edward Goodrich Acheson (1856–1931). The process consists of heating a mixture of clay (aluminum silicate) and powdered coke (carbon) in an iron bowl. The reaction involves the production of silicon carbide, which loses silicon at 4150 °C to leave graphite.
glycoside → glikozid
Glycoside is one of a group of organic compounds in which a sugar group is bonded through its anomeric carbon to another group via a glycosidic bond. The sugar group is known as the glycon and the non-sugar group as the aglycon. According to the IUPAC definition, all disaccharides and polysaccharides are glycosides where the aglycone is another sugar.
In the free hemiacetal form, sugars will spontaneously equilibrate between the α and β anomers. However, once the glycosidic bond is formed, the anomeric configuration of the ring is locked as either α or β. Therefore, the alpha and beta glycosides are chemically distinct. They will have different chemical, physical, and biological properties. Many glycosides occur abundantly in plants, especially as flower and fruit pigments.
The term glycoside was later extended to cover not only compounds in which the anomeric hydroxy group is replaced by a group -OR, but also those in which the replacing group is -SR (thioglycosides), -SeR (selenoglycosides), -NR1R2 (N-glycosides), or even -CR1R2R3 (C-glycosides). Thioglycoside and selenoglycoside are legitimate generic terms; however the use of N-glycoside, although widespread in biochemical literature, is improper and not recommended here (glycosylamine is a perfectly acceptable term). C-Glycoside is even less acceptable. All other glycosides are hydrolysable; the C-C bond of C-glycosides is usually not. The use and propagation of names based on C-glycoside terminology is therefore strongly discouraged.
gravimetry → gravimetrija
Gravimetry is the quantitative measurement of an analyte by weighing a pure, solid form of the analyte. Since gravimetric analysis is an absolute measurement, it is the principal method for analysing and preparing primary standards.
A typical experimental procedure to determine an unknown concentration of an analyte in a solution is as follows:
- quantitatively precipitate the analyte from the solution
- collect the precipitate by filtering and wash it to remove impurities
- dry the solid in an oven to remove the solvent
- weigh the solid on an analytical balance
- calculate the analyte concentration in the original solution based on the weight of the precipitate.
half-life → vrijeme poluraspada
For a simple radioactive decay process, half-life, t1/2, is defined as the time required for the activity of a given radioactive isotopes to decrease to half its value by that process.
The half-life is a characteristic property of each radioactive isotope and is independent of its amount or condition.
Citing this page:
Generalic, Eni. "Spontani proces." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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