Hydrate is a term which means different things in inorganic chemistry and organic chemistry. Inorganic chemistry is the branch of chemistry concerned with the properties and reactions of inorganic compounds. ... Organic chemistry is a specific discipline within the subject of chemistry. ...

In organic chemistry, a hydrate is a compound formed by the addition of water to a host molecule. Thus ethanol could be considered to be the hydrate of ethylene. These substances do not contain water as such, but have their constituents (hydrogen, oxygen, hydroxyl) so arranged that water may be eliminated. Hence, hydrates are derivatives of, or compounds with, hydroxyl. Water is a chemical substance that is essential to all known forms of life. ... Ethylene (or IUPAC name ethene) is the chemical compound with the formula CH2CH2. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ...

In inorganic chemistry, hydrates contain water molecules that are either bound to a metal center or crystallized with the metal complex. Such hydrates are also said to contain "water of crystallization" or "water of hydration". If the water is heavy water, where the hydrogen consists of the isotope deuterium, then the term deuterate may be used in place of hydrate. Heavy water is dideuterium oxide, or D2O or 2H2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. ... Isotopes are any of the several different forms of an element each having different atomic mass. ... Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of planet Earth of approximately one atom in 6500 of hydrogen (~154 PPM). ...

The notation of hydrous compound · nH₂O, where n is the number of water molecules per molecule of salt, is commonly used to show that a salt is hydrated. The n is usually a low integer, though it is possible for fractional values to exist. In a monohydrate n is one, in a hexahydrate n is 6 etc. Such water is also referred to as water of crystallization. Examples include borax, chloral hydrate, clathrate hydrates (a class of solid hydrates of gases), and chalcanthite. Gas hydrates are clathrate hydrates: water ice with gas molecules trapped within. When the gas is methane it is called a methane hydrate. General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... The integers are commonly denoted by the above symbol. ... Water of crystallization is water that is tightly associated with crystalline metal salts, and remains after drying in a fixed proportion to the salt. ... It has been suggested that Sodium boric acid be merged into this article or section. ... Chloral hydrate, also known as trichloroacetaldehyde monohydrate, 2,2,2-trichloro-1,1-ethanediol, and under the tradenames Aquachloral, Novo-Chlorhydrate, Somnos, Noctec, and Somnote, is a sedative and hypnotic drug as well as a chemical reagent and precursor. ... Clathrate hydrates are a class of solids in which gas molecules occupy cages made up of hydrogen-bonded water molecules. ... Chalcanthite, whose name derives from the Greek, chalkos and anthos, meaning copper flower, is a richly-colored blue/green water-soluble sulfate mineral, commonly found in the late-stage oxidation zones of copper deposits. ... Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. ... Methane is a significant and plentiful fuel which is the principal component of natural gas. ... Burning ice. Methane released by heating burns, water drips. ...

The opposite of a hydrate is an anhydrate, such substances contain no water or form no water upon heating. To meet Wikipedias quality standards, this article or section may require cleanup. ...

Construction

The presence of hydrates is quite purposeful in the three fields of endeavour. Generally, in construction and refractories, inorganic binders are often deprived of water during manufacture. For instance, both in cement and gypsum products, heat is applied to the raw materials. Once water is added on a construction site, the powder is re-hydrated and able to form bonds with other substances that are present. Thus, one goes from powder, to slurry, or paste and then forms "cement stone". Water that is not chemically bound, or converted into hydrates, can come off again as steam, especially due to the heat of hydration, with cement products in particular, which undergo an exothermic chemical reaction with water. Cranes are essential in large construction projects, such as this skyscraper In project architecture and civil engineering, construction is the building or assembly of any infrastructure on a site. ... In the most general sense of the word, cement is a binder, a substance which sets and hardens independently, and can bind other materials together. ... Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. // Heating gypsum to between 100°C and 150°C (302°F) partially dehydrates the mineral by driving off exactly 75% of the water contained in its chemical structure. ... In physics, heat, symbolized by Q, is defined as energy in transit. ... Water is a chemical substance that is essential to all known forms of life. ... In physical chemistry, and in engineering, steam refers to vaporized water. ... In thermodynamics, the word exothermic describes a process or reaction that releases energy in the form of heat. ...

Generally, the longer one can keep cementitious products wet, immediately after placement, the better. The wetter cementitious products are kept, the more water will be converted into hydrates, instead of evaporating off due to the heat of hydration and other environmental influences. Premature drying is a cause for severe concrete problems, such as cracking and shrinkage.

Passive fire protection

Avoiding premature drying is important to all other cementitious building products, such as spray fireproofing and firestop mortars in particular, where the slightest cracking can lead to rejections. The chemically bound water, is the source for endothermic reactions when exposed to fire. Fire temperatures in a building can reach 1100°C, depending on the fuel present and the availability of oxygen. The presence of hydrates keep the item exposed to the heat at or below 100 °C, until all the water is spent. Therefore, the more hydrates, the longer the fire-resistance duration. This is what lends fire-resistive characteristics to basic, or "old" building materials, such as gypsum, concrete or plaster. Fireproofing, a passive fire protection measure, subject to bounding, refers to the act of making materials or structures more resistant to fire, or to those materials themselves. ... A firestop is a passive fire protection system of various components used to seal openings in fire-resistance rated wall and/or floor assemblies through bounding. ... In thermodynamics, the word endothermic describes a process or reaction that absorbs energy in the form of heat. ... Just-lit match Fire is a self-sustaining oxidation process accompanied by heat and light in the form of a glow or flames. ... For other uses, see Building (disambiguation). ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... In physics, heat, symbolized by Q, is defined as energy in transit. ... Building material is any material which is used for a construction purpose. ... Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ... // Gypsum plaster Plaster of Paris, or simply plaster, is a type of building material based on calcium sulfate hemihydrate, nominally (CaSOâ‚„)â‚‚*Hâ‚‚O. It is created by heating gypsum to about 150 ℃, 2(CaSOâ‚„ · 2Hâ‚‚O) → (CaSOâ‚„)â‚‚ · Hâ‚‚O + 3 Hâ‚‚O (released as steam). ...

Space physics

Fire-resistance duration is important to many high-tech PFP products such as intumescent and endothermic paints, wraps and tiles, such as those used in space physics, for re-entry vehicles. Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... Space physics, also known as space plasma physics, is the study of plasmas as they occur naturally in the universe. ...

See also

• Passive fire protection