Precipitation (chemistry): Difference between revisions
wikademia>Tristanb quick cut/paste from precipitate. don't worry i'll merge it soon. |
wikademia>Tristanb improving quick merge |
||
| Line 1: | Line 1: | ||
In [[chemistry]], '''precipitation''' is the condensation of a [[solid]] from a [[solution]]. This occurs when the solution is [[saturated]], whereupon the solid forms from the solute phase, and usually sinks to the bottom of the solution. | In [[chemistry]], '''precipitation''' is the condensation of a [[solid]] from a [[solution]] during a [[chemical reaction]]. This occurs when the solution is [[saturated]], whereupon the solid forms from the solute phase, and usually sinks to the bottom of the solution. | ||
This effect is useful in many industrial and scientific applications whereby a chemical reaction may produce a solid that can be collected from the solution by various methods (e.g. filtration, decanting, centrifuging). | This effect is useful in many industrial and scientific applications whereby a chemical reaction may produce a solid that can be collected from the solution by various methods (e.g. filtration, decanting, centrifuging). | ||
==Detection of cations== | ==Detection of cations== | ||
| Line 12: | Line 8: | ||
To identify the cation, the colour of the precipitate and its solubility in excess are noted. | To identify the cation, the colour of the precipitate and its solubility in excess are noted. | ||
== | ==External links== | ||
* http://www.chs.edu.sg/~limth/lessons/2002/qa/cations.htm | * http://www.chs.edu.sg/~limth/lessons/2002/qa/cations.htm | ||
Revision as of 04:29, 28 March 2004
In chemistry, precipitation is the condensation of a solid from a solution during a chemical reaction. This occurs when the solution is saturated, whereupon the solid forms from the solute phase, and usually sinks to the bottom of the solution.
This effect is useful in many industrial and scientific applications whereby a chemical reaction may produce a solid that can be collected from the solution by various methods (e.g. filtration, decanting, centrifuging).
Detection of cations
Precipitate formation is useful in detecting the type of cation in an unknown salt. To do this, an alkali first reacts with the unknown salt to produce a precipitate which is the hydroxide of the unknown salt.
To identify the cation, the colour of the precipitate and its solubility in excess are noted.