|
Gas Evolution Reaction
A gas evolution reaction is a chemical reaction in which one of the end products is a gas such as oxygen or carbon dioxide. Gas evolution reactions may be carried out in a fume chamber when the gases produced are poisonous when inhaled or explosive. Examples * A replacement reaction concerning zinc metal and dilute sulfuric acid. : Zn + H_2SO_4 (dil) -> ZnSO_4 + H_2 ^ : In this example, diatomic hydrogen gas is released. Dilute hydrochloric acid can be used in place of dilute sulfuric acid. * A replacement reaction where gaseous hydrogen chloride and fluorine gas react to release diatomic chlorine gas (because fluorine is more electronegative): : 2HCl + F_2 -> 2HF + Cl_2 ^ See also * Gasogene * Kipps apparatus * Gas generator * Thermal decomposition Thermal decomposition, or thermolysis, is a chemical decomposition of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, energy change as new products are generated. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine
Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidizing agent, oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Electronegativity#Pauling electronegativity, Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval Alchemy, alchemists, which commonly involved the heating of chloride Salt (chemistry), salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and . However, the nature of fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen Evolution
Oxygen evolution is the chemical process of generating diatomic oxygen (O2) by a chemical reaction, usually from water, the most abundant oxide compound in the universe. Oxygen evolution on Earth is effected by biotic oxygenic photosynthesis, photodissociation, hydroelectrolysis, and thermal decomposition of various oxides and oxyacids. When relatively pure oxygen is required industrially, it is isolated by distilling liquefied air. Natural oxygen evolution is essential to the biological process of all complex life on Earth, as aerobic respiration has become the most important biochemical process of eukaryotic thermodynamics since eukaryotes evolved through symbiogenesis during the Proterozoic eon, and such consumption can only continue if oxygen is cyclically replenished by photosynthesis. The various oxygenation events during Earth's history had not only influenced changes in Earth's biosphere, but also significantly altered the atmospheric chemistry. The transition of Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Decomposition temperature definition A simple substance (like water) may exist in equilibrium with its thermal decomposition products, effectively halting the decomposition. The equilibrium fraction of decomposed molecules increases with the temperature. Since thermal decomposition is a kinetic process, the observed temperature of its beginning in most instances will be a function of the experimental conditions and sensitivity of the experimental setup. For a rigorous depiction of the process, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Generator
A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a rocket propellant to generate large quantities of gas. The gas is typically used to drive a turbine rather than to provide thrust as in a rocket engine. Gas generators of this type are used to power turbopumps in rocket engines, in a gas-generator cycle. It is also used by some auxiliary power units to power electric generators and hydraulic pumps. Another common use of the term is in the industrial gases industry, where gas generators are used to produce gaseous chemicals for sale. For example, the chemical oxygen generator, which delivers breathable oxygen at a controlled rate over a prolonged period. During World War II, portable gas generators that converted Coke (fuel), coke to producer gas were used to power vehicles as a way o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kipps Apparatus
Kipp's apparatus, also called a Kipp generator, is an apparatus designed for preparation of small volumes of gases. It was invented around 1844 by the Dutch pharmacist Petrus Jacobus Kipp and widely used in chemical laboratories and for demonstrations in schools into the second half of the 20th century. It later fell out of use, at least in laboratories, because most gases then became available in small gas cylinders. These industrial gases are much purer and drier than those initially obtained from a Kipp apparatus without further processing. Design and operation The apparatus is usually made of glass, or sometimes of polyethylene, and consists of three vertically stacked chambers, roughly resembling a snowman. The upper chamber extends downward as a tube that passes through the middle chamber into the lower chamber. There is no direct path between the middle and upper chambers, but the middle chamber is separated from the lower chamber by a retention plate, such as a conical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gasogene
The gasogene (or gazogene or seltzogene) is a late Victorian device for producing carbonated water. It consists of two linked glass globes: the lower contained water or other drink to be made sparkling, the upper a mixture of tartaric acid and sodium bicarbonate that reacts to produce carbon dioxide. The produced gas pushes the liquid in the lower container up a tube and out of the device. The globes are surrounded by a wicker or wire protective mesh, as they have a tendency to explode. The earliest occurrence of the word noted in the ''Oxford English Dictionary'' dates from 1853, quoting a reference in ''Practical Mechanic's Journal'' on "Gaillard and Dubois' 'Gazogene' or Aerated Water apparatus". In popular culture A gasogene is mentioned as a residential fixture at 221B Baker Street in Arthur Conan Doyle's Sherlock Holmes story " A Scandal in Bohemia": "With hardly a word spoken, but with a kindly eye, he waved me to an armchair, threw across his case of cigars, and indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronegative
Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity, the more an atom or a substituent group attracts electrons. Electronegativity serves as a simple way to quantitatively estimate the bond energy, and the sign and magnitude of a bond's chemical polarity, which characterizes a bond along the continuous scale from covalent to ionic bonding. The loosely defined term electropositivity is the opposite of electronegativity: it characterizes an element's tendency to donate valence electrons. On the most basic level, electronegativity is determined by factors like the nuclear charge (the more protons an atom has, the more "pull" it will have on electrons) and the number and locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extremely Reactivity (chemistry), reactive as it reacts with all other Periodic table, elements except for the light Noble gas, noble gases. It is highly toxicity, toxic. Among the elements, fluorine ranks Abundance of the chemical elements, 24th in cosmic abundance and 13th in crustal abundance. Fluorite, the primary mineral source of fluorine, which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb meaning gave the mineral its name. Proposed as an element in 1810, fluorine proved difficult and dangerous to separate from its compounds, and several early experimenters died or sustained injuries from their attempts. Only in 1886 did French chemist He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Chloride
The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl. Reactions Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a Polar-covalent bond, polar covalent bond. The chlorine atom is much more Electronegativity, electronegative than the hydrogen atom, which makes this bond polar. Consequently, the molecule has a large Molecular dipole moment, dipole moment with a negative partial charge (δ−) at the chlorine atom and a positive partial charge (δ+) at the hydrogen atom. In part because of its high polarity, HCl is very soluble in water (and in other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrochloric Acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans. Hydrochloric acid is an important laboratory reagent and industrial chemical. Etymology Because it was produced from halite, rock salt according to the methods of Johann Rudolph Glauber, hydrochloric acid was historically called by European alchemists ''spirits of salt'' or ''acidum salis'' (salt acid). Both names are still used, especially in other languages, such as , , , , , , , , , , (''ensan''), zh, 盐酸 (''yánsuān''), and (''yeomsan''). Gaseous HCl was called ''marine acid air''. The name ''muriatic acid'' has the same origin (''muriatic'' means "pertaining to brine or salt", hence ''muriate'' means hydrochloride), and this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
