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Home >> Chemistry Dictionary >>Ebonite - Einstein Equation
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Earth.
The planet that orbits the sun between the planets Venus and Mars. The earth consists of three layers; the gaseous atmosphere (see earth’s atmosphere), the liquid hydrosphere, and the solid lithosphere. The solid part of the earth also consists of three layers; the crust with a mean thickness of about 32 km. under the land and 10 km under the seas; the mantle, which extends some 2900 km below the crust; and the core, part of which is believed to be liquid. The composition of the crust is; oxygen 47%, silicon 28%, aluminium 8%, iron 4.5%, calcium 3.5%, sodium and potassium 2.5% each, and magnesium 2.2%. Hydrogen, carbon, phosphorus, and sulphur are all present to an extent of less than 1%.
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Earth’s atmosphere. The gas that surrounds the earth. The composition of dry air at sea level is; nitrogen 78.08%, oxygen 20.95% argon 0.93%, carbon dioxide 0.03%, neon 0.0018%, helium 0.0005%, Krypton 0.0001%, and xenon 0.00001%. In addition to water vapour, air in some localities contains sulphur compounds, hydrogen peroxide, hydrocarbons and dust particles.
Earth’s crust. A solid outer layer of the earth; the most abundant elements in earth’s crust are O, Na, Si, Al, Fe, Ca, K and Mg. They form oxides, silicates, aluminium silicates, carbonates, sulphates which occur in various rocks.
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Ebonite. Hard rubber, vulcanite. A hard black, inert materials made by vulcanizing mixtures with a rubber; sulphur mixture near 2 : 1 and with less than 4% of the sulphur uncombined.
Echelon. A form of interferemeter which is used in spectroscopy to study hyperfine line structure.
Edta. Ethylenediaminetetracetic acid, (HOOCCH2)2N(CH2)N(CH2COOH)2 A compound used as a chelating agent in inorganic chemistry.
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Effervescene. The process in which a crystalline hydrate loses water, forming a powdery deposit on crystals.
Efflorescence. The loss of water by a salt hydrate arising because the pressure of water over the hydrate is greater than the partial pressure of water in the atmosphere.
Effusion. The flow of a gas through a small aperture. The relative rate at which gases effuse, under the same conditions, is approximately inversely proportional to the square roots of their densities
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Einstein. A unit of radiant energy. If every molecule in a gram molecule of a substance absorbs one quantum of light, the total energy absorbsed is Lhv, were L is the Avogadro number, h is Planck’s constant, and v the frequency of the light. L = 6.06×1022; h = 6.548 × 10-27 erg sec., and therefore for red light of frequency 4 × 1014, one Einstein = 1.588 × 1011 ergs.
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Einsteinium. Es. At. no. 99, 253Es (20 days) and 254Es (270 days) may be formed by multiple neutron irradiation of Am, Pu and Cm; it is purified by ion exchange chromatography. The metal has not yet been prepared.
Einstein equation (1). The mass-energy relationship announced by Einstein in 1905 in the form E = mc2, where E is a quantity of energy, m its mass, and c is the speed of light. It presents the concept that energy possesses mass. (2) The relationship Emax = hf – W, where Emax is the maximum kinetic energy of electrons emitted in the photoemissive effect, h is the Planck constant, f the frequency of the incident radiation, and W the work function of the emitter. This is also written Emax = hf - fe, where e is the electronic charge and f are distinguished as work function energy and work function potential.) The equation can also be applied to photoemission from gases, when it has the from: E = hf = I, where I is the ionization potential of the gas.
Ejector. A simple non-mechanical device used for the pumping of liquids and gases.
Electric arc furnace. A furnace used in melting metals to make alloys, especially in steel manufacture, in which the heat source is an electric arc. In the direct arc furnace, such as the Heroult furnace, an area is formed between the metal and an electrode. In the indirect-are furnace, such as the Stassano furnace, the are is formed between two electrodes and the heat is radiated onto the metal.
Electrical energy. The energy associated with electric charges and their movements. Measured in watt seconds (joules) or kilowatt-hours. On kilowatt-hour equals 3.6 × 106 joules or 8.598, 45 × 105 calories.
Electrochemical equivalent. The weight of an element liberated from its ions or converted into them by unit quantity (1 coulomb) of electricity.
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