CHEMISTRY GLOSSARY
molar enthalpy of melting → molarna entalpija taljenja
Molar enthalpy of melting (Δs lH) is a change of enthalpy during melting divided by the molarity of a solid matter, and is equal to the energy used when melting is conducted under constant pressure.
Graham’s law → Grahamov zakon
Graham’s law is the rates at whish gases diffuse are inversely proportional to the square roots of their densities. This principle is made use of in the diffusion method of separating isotopes. The law was formulated in 1829 by British chemist Thomas Graham (1805-1869).
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.
mole ratio → količinski omjer
Mole ratio is equal to a proportion of one component quantity (nA) and the quantity of other component (nB).
Gratzel solar cell → Gratzelova sunčeva ćelija
Grätzel solar cell is photoelectrochemical cell, developed by Michael Grätzel and collaborators, simulates some characteristics of the natural solar cell, which enables photosynthesis take place. In natural solar cell the chlorophyll molecules absorb light (most strongly in the red and blue parts of the spectrum, leaving the green light to be reflected). The absorbed energy is sufficient to knock an electron from the excited chlorophyll. In the further transport of electron, other molecules are involved, which take the electron away from chlorophyll. In Grätzel cell, the tasks of charge-carrier generation and transport are also assigned to different species.
His device consists of an array of nanometre-sized crystallites of the semiconductor titanium dioxide, welded together and coated with light-sensitive molecules that can transfer electrons to the semiconductor particles when they absorb photons. So, light-sensitive molecules play a role equivalent to chlorophyll in photosynthesis. In Grätzel cell, the light-sensitive molecule is a ruthenium ion bound to organic bipyridine molecules, which absorb light strongly in the visible range; titanium dioxide nanocrystals carry the received photoexcited electrons away from electron donors. On the other hand, a donor molecule must get back an electron, so that it can absorb another photon. So, this assembly is immersed in a liquid electrolyte containing molecular species (dissolved iodine molecules) that can pick up an electron from an electrode immersed in the solution and ferry it to the donor molecule. These cells can convert sunlight with efficiency of 10 % in direct sunlight and they are even more efficient in diffuse daylight.
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.
monochromator → monokromator
Monochromator (from the Greek words mono and chroma meaning single and colour) is an optical device based on dispersion of light by one or more prisms or diffraction gratings into its constituent wavelengths, which are utilized in turn.Citing this page:
Generalic, Eni. "S.t.p.." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
English
