Chemical combination

The term lime also has a broad coimotation and frequently is used in referring to limestone. According to precise definition, lime can only be a burned form quicklime, hydrated lime, or hydraiflic lime. These products are oxides or hydroxides of calcium and magnesium, except hydraiflic types in which the CaO and MgO are chemically combined with impurities. The oxide is converted to a hydroxide by slaking, an exothermic reaction in which the water combines chemically with the lime. These reversible reactions for both high calcium and dolomitic types are Quicklime... 

THE COMBINED CHEMICAL AND PHYSICAL INFLUENCES IN SAMPLE PREPARATION... 

The need for an overall and combined chemical structure and data search system became clear to us some time ago, and resulted in the decision to build CHIRBASE, a molecular-oriented factual database. The concept utilized in this database approach is related to the importance of molecular interactions in chiral recognition mechanisms. Solely a chemical information system permits the recognition of the molecular key fingerprints given by the new compound among thousands of fingerprints of known compounds available in a database. 

Since methane is almost always a byproduct of organic decay, it is not surprising that vast potential reserves of methane have been found trapped in ocean floor sediments. Methane forms continually by tiny bacteria breaking down the remains of sea life. In the early 197Qs it was discovered that this methane can dissolve under the enormous pressure and cold temperatures found at the ocean bottom. It becomes locked in a cage of water molecules to form a methane hydrate (methane weakly combined chemically with water). This "stored" methane is a resource often extending hundreds of meters down from the sea floor. 

When the water is added to the final dry cement material, the hydration of the cement begins immediately. The water is combined chemically with the cement material to eventually form a new immobile solid. As the cement hydrates, it will bond to the surrounding surfaces. This cement bonding is complex and depends on the type of surface to be cemented. Cement bonds to rock by a process of crystal growth. Cement bonds to the outside of a casing by filling in the pit spaces in the casing body [163]. 

The manner in which a film is formed on a surface by CVD is still a matter of controversy and several theories have been advanced to describe the phenomena. ] A thermodynamic theory proposes that a solid nucleus is formed from supersaturated vapor as a result of the difference between the surface free energy and the bulk free energy of the nucleus. Another and newer theory is based on atomistic nucle-ation and combines chemical bonding of solid surfaces and statistical mechanics. These theories are certainly valuable in themselves but considered outside the scope of this book. 

Ayhan S, Baran CN, Yavuzer R, Latifoglu O, Ceneto-glu S, Baran NK (1998) Combined chemical peeling and dermabrasion for deep acne and posttraumatic scars as well as aging face. Plast Reconstr Surg 102(4) 1238-1246... 

Horton CE, Sadove RC (1987) Refinements in combined chemical peel and simultaneous abrasion of the face. Ann Plast Surg 19(6) 504-511... 

Why Is a Combined Chemical Peel Useful for Treating Melasma ... 

A chemical transformation, on the other hand, produces new substances. For example, when magnesium metal bums in air, elemental magnesium metal and molecular oxygen combine chemically to form magnesium oxide, a white solid containing Mg and O atoms in 1 1 ratio. This is a chemical transformation that rearranges the atoms in Mg and O2 to yield MgO. 

I) Chemspor which is a combined chemical and biological indicator the ampoule contains a spore suspension in culture medium together with a second, smaller ampoule which contains a chemical indicator. 

Sometimes, part design requires multiple polymer layers. For example, an automotive gasoline tank can consist of both nylon and crosslinked polyethylene to provide combined chemical [-, resistance and strength, To produce multilayered parts, the first polymer, which will form... 

Within each category there are many variants. There are also hybrids, which combine chemical structures borrowed from more than one family of catalysts. 

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