CHEMISTRY GLOSSARY

Avogadro, Amadeo    →   Avogadro, Amadeo

Amadeo Avogadro (1776-1856) is an Italian chemist and physicist that proposed a correct molecular explanation for Gay-Lussac’s law of combining volumes. His work provided a simple way to determine atomic weights and molecular weights of gases. He is published a theory about the movement of particles in gases that became known as Avogadro’s Law.

blackbody    →   crno tijelo

In radiation physics, an ideal blackbody is a theoretical object that absorbs all the radiant energy falling upon it and emits it in the form of thermal radiation. Planck’s radiation law gives the power radiated by a unit area of blackbody, and the Stefan-Boltzman law expresses the total power radiated.

base    →   baza

Historically, base is a substance that yields an OH - ion when it dissociates in solution, resulting in a pH>7. In the Brønsted definition, a base is a substance capable of accepting a proton in any type of reaction. The more general definition, due to G.N. Lewis, classifies any chemical species capable of donating an electron pair as a base. Typically, bases are metal oxides, hydroxides, or compounds (such as ammonia) that give hydroxide ions in aqueous solution.

Boltzmann constant    →   Boltzmannova konstanta

The Boltzmann constant (k or k_B) is the physical constant describing the relationship between the thermodynamic temperature and the average kinetic energy of particles in a gas. It equals the molar gas constant R divided by the Avogadro constant N_A and has the value 1.380 648 52(79)×10^-23 J/K. It is named after the Austrian physicist Ludwig Eduard Boltzmann (1844-1906).

borane    →   borani

Borane is any of the group of compounds of boron and hydrogen (B₂H₆, B₄H₁₀, B₅H₉, B₅H₁₁...), many of which can be prepared by action of acid on magnesium boride (Mg₃B₂). Boranes are a remarkable group of compounds in that their structures cannot be described using the conventional two-electron covalent bond model.

Bragg angle    →   Braggov kut

Bragg angle (Θ) is the angle between an incident X-ray beam and a set of crystal planes for which the secondary radiation displays maximum intensity as a result of constructive interference. British physicist Sir William Henry Bragg and his son Sir William Lawrence Bragg developed a simple relation for scattering angles, now call Bragg’s law.

which relates the angle θ between a crystal plane and the diffracted X-ray beam, the wavelength λ of the x-rays, the crystal plane spacing d, and the diffraction order n (any integer).

The diffraction experiment as presently considered is intended to provide quantitative information on the lattice constant and shape characteristics of the unit cell.

Dalton, John    →   Dalton, John

Dalton, John (1766-1844) British chemist and physicist. In 1801 he formulated his law of partial pressures (Dalton’s law), but he is best remembered for Dalton’s atomic theory, which he announced in 1803. Dalton also studied colour blindness (a condition, once called Daltonism, that he shared with his brother).

electron volt    →   elektronvolt

Electron volt (eV) is a non-SI unit of energy used in atomic and nuclear physics, equal to approximately 1.602 177×10^-19 J. The electron volt is defined as the kinetic energy acquired by an electron upon acceleration through a potential difference of 1 V.

heat    →   toplina

Heat is a form of energy associated with and proportional to molecular motion. It can be transferred from one body to another by radiation, conduction, or convection.

Einstein, Albert    →   Einstein, Albert

Albert Einstein (1879-1955) is a German born American physicist, who took Swiss nationality in 1901. A year later he went to work in the Bern patent office. In 1905. he published five enormously influential papers, one on Brownian movement, one on the photoelectric effect, one on the special theory of relativity, and one on energy and inertia (which included the famous expression E = mc²). In 1915 he published the general theory of relativity, concerned mainly with gravitation. In 1921 he was awarded the Nobel Prize. In 1933, as a Jew, Einstein decided to remain in the USA (where he was lecturing), as Hitler had come to power. For the remainder of his life he sought a unified field theory. In 1939 he informed president Roosevelt that an atom bomb was feasible and that. Germany might be able to make one.