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Abundance Of The Chemical Elements
The abundance of the chemical elements is a measure of the Type–token distinction#Occurrences, occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (chemistry), ''mass fraction'' (in commercial contexts often called ''weight fraction''), by ''mole fraction'' (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by ''volume fraction''. Volume fraction is a common abundance measure in mixed gases such as planetary atmospheres, and is similar in value to molecular mole fraction for gas mixtures at relatively low densities and pressures, and ideal gas mixtures. Most abundance values in this article are given as mass fractions. The abundance of chemical elements in the universe is dominated by the large amounts of hydrogen and helium which were produced during Big Bang nucleosynthesis. Remaining elements, making up only about 2% of the universe, were lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type–token Distinction
The type–token distinction is the difference between a ''type'' of objects (analogous to a ''class'') and the individual ''tokens'' of that type (analogous to ''instances''). Since each type may be instantiated by multiple tokens, there are generally more tokens than types of an object. For example, the sentence "A Rose is a rose is a rose" contains three word types: three word tokens of the type ''a'', two word tokens of the type ''is,'' and three word tokens of the type ''rose''. The distinction is important in disciplines such as logic, linguistics, metalogic, typography, and computer programming. Overview The type–token distinction separates ''types'' (abstract descriptive concepts) from ''tokens'' (objects that instantiate concepts). For example, in the sentence "''the bicycle is becoming more popular''" the word ''bicycle'' represents the abstract concept of bicycles and this abstract concept is a type, whereas in the sentence "''the bicycle is in the garage''", it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pure Water
Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently purified by other processes including capacitive deionization, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation, or electrodeionization. Combinations of a number of these processes have come into use to produce ultrapure water of such high purity that its trace contaminants are measured in parts per billion (ppb) or parts per trillion (ppt). Purified water has many uses, largely in the production of medications, in science and engineering laboratories and industries, and is produced in a range of purities. It is also used in the commercial beverage industry as the primary ingredient of any given trademarked bottling formula, in order to maintain product consistency. It can be produced on-site for imm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way Galaxy
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a D25 isophotal diameter estimated at , but only about 1,000 light-years thick at the spiral arms (more at the bulge). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-years (613 kpc). The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, forming part of the Virgo Supercluster which is itself a component of the Laniakea Supercluster. It is estimated to contain 100–400 billion stars and at least that number of planets. The Solar System is located at a radius of about 27,000 light-years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ideal Gas Law
The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stated by Benoît Paul Émile Clapeyron in 1834 as a combination of the empirical Boyle's law, Charles's law, Avogadro's law, and Gay-Lussac's law. The ideal gas law is often written in an empirical form: pV = nRT where p, V and T are the pressure, volume and Thermodynamic temperature, temperature respectively; n is the amount of substance; and R is the ideal gas constant. It can also be derived from the microscopic kinetic theory of gases, kinetic theory, as was achieved (independently) by August Krönig in 1856 and Rudolf Clausius in 1857. Equation The state function, state of an amount of gas is determined by its pressure, volume, and temperature. The modern form of the equation relates these simply in two main forms. The temperature us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disproportionation
In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation state. The reverse of disproportionation, such as when a compound in an intermediate oxidation state is formed from precursors of lower and higher oxidation states, is called ''comproportionation'', also known as ''symproportionation''. More generally, the term can be applied to any desymmetrizing reaction where two molecules of one type react to give one each of two different types: : This expanded definition is not limited to redox reactions, but also includes some molecular autoionization reactions, such as the self-ionization of water. In contrast, some authors use the term ''redistribution'' to refer to reactions of this type (in either direction) when only ligand exchange but no redox is involved and distinguish such processes from disproportionation and comproportionati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionization
Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive Electric charge, charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules, electrons, positrons, protons, antiprotons, and ions, or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can result in the formation of ion pairs. Ionization can occur through radioactive decay by the internal conversion process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected. Uses Everyday examples of gas ionization occur within a fluorescent lamp or other electrical discharge lamps. It is also used in radiation detectors such as the Geiger- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatomic
Diatomic molecules () are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen () or oxygen (), then it is said to be homonuclear molecule, homonuclear. Otherwise, if a diatomic molecule consists of two different atoms, such as carbon monoxide () or nitric oxide (), the molecule is said to be heteronuclear molecule, heteronuclear. The bond in a homonuclear diatomic molecule is non-polar. The only chemical elements that form stable homonuclear diatomic molecules at standard temperature and pressure (STP) (or at typical laboratory conditions of 1 bar (pressure), bar and 25 °C) are the gases hydrogen (), nitrogen (), oxygen (), fluorine (), and chlorine (), and the liquid bromine (). The noble gases (helium, neon, argon, krypton, xenon, and radon) are also gases at STP, but they are monatomic. The homonuclear diatomic gases and noble gases together are called "ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter's Outer Atmosphere
The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is mostly made of molecular hydrogen and helium in roughly Sun#Composition, solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide, and water. Although water is thought to reside deep in the atmosphere, its directly-measured concentration is very low. The nitrogen, sulfur, and noble gas abundances in Jupiter's atmosphere exceed solar values by a factor of about three. The atmosphere of Jupiter lacks a clear lower boundary and gradually transitions into the liquid interior of the planet. From lowest to highest, the atmospheric layers are the troposphere, stratosphere, thermosphere and exosphere. Each layer has characteristic temperature gradients. The lowest layer, the troposphere, has a complicated system of clouds and hazes composed of layers of ammonia, ammonium hydrosulfide, and water. The upper ammonia clouds visible at Jup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium
Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the Chemical element, elements, and it does not have a melting point at standard pressures. It is the second-lightest and second-most Abundance of the chemical elements, abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and Jupiter, because of the very high nuclear binding energy (per nucleon) of helium-4 with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter. Under standard conditions, hydrogen is a gas of diatomic molecules with the chemical formula, formula , called dihydrogen, or sometimes hydrogen gas, molecular hydrogen, or simply hydrogen. Dihydrogen is colorless, odorless, non-toxic, and highly combustible. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found as the gas (dihydrogen) and in molecular forms, such as in water and organic compounds. The most common isotope of hydrogen (H) consists of one proton, one electron, and no neutrons. Hydrogen gas was first produced artificially in the 17th century by the reaction of acids with metals. Henry Cavendish, in 1766–1781, identified hydrogen gas as a distinct substance and discovere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. Its diameter is 11 times that of Earth and a tenth that of the Sun. Jupiter orbits the Sun at a distance of , with an orbital period of . It is the List of brightest natural objects in the sky, third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. Its name derives from that of Jupiter (god), Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas-giant Planet
A gas giant is a giant planet composed mainly of hydrogen and helium. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranus and Neptune are a distinct class of giant planets composed mainly of heavier volatile substances (referred to as " ices"). For this reason, Uranus and Neptune are often classified in the separate category of ice giants. Jupiter and Saturn consist mostly of hydrogen and helium, with heavier elements making up between 3 and 13 percent of their mass.The Interior of Jupiter, Guillot et al., in ''Jupiter: The Planet, Satellites and Magnetosphere'', Bagenal et al., editors, Cambridge University Press, 2004 They are thought to have an outer layer of compressed molecular hydrogen surrounding a layer of liquid metallic hydrogen, with a molten rocky core inside. The outermost portion of their hydrogen atmosphere contains many layers of visible clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
