05-09-2012, 11:03 AM
Chemical reaction
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A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity.
DEFINITIONS
CHEMICAL COMBINATION:- In a chemical combination reaction, two or more simple substances combine to form a more complex substance. A+B→AB
CHEMICAL DISPLACEMENT:- In a chemical displacement reaction, a single uncombined element replaces another in a compound. AB+C → AC+B
CHEMICAL DOUBLE DISPLACEMENT:- In a double replacement reaction, parts of two compounds switch places to form two new compounds. AB+CD → AD+CB
CHEMICAL DECOMPOSITION
Chemical decomposition, analysis or breakdown is the separation of a chemical compound into elements or simpler compounds. It is sometimes defined as the exact opposite of a chemical synthesis. Chemical decomposition is often an undesired chemical reaction. The stability that a chemical compound ordinarily has is eventually limited when exposed to extreme environmental conditions like heat, radiation , humidity or the acidity of a solvent. The details of decomposition processes are generally not well defined, as a molecule may break up into a host of smaller fragments. Chemical decomposition is exploited in several analytical techniques, notably mass spectrometry, traditional gravimetric analysis, and thermo-gravimetric analysis.