What is Chemical substance?
[[Image:Kochendes wasser02.jpg|thumb|right|Water and steam are two different forms of the same chemical substance]] A '''chemical substance''' is any [[material]] with a known [[chemical composition]].<ref>Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. ''General Chemistry'', 4th ed., p5, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.</ref> For example, [[Water (molecule)|water]] has the same properties and the same [[ratio]] of [[hydrogen]] to [[oxygen]] whether it came from a [[river]] or was made in a [[laboratory]]. Typical chemical substances found in the home include water, [[salt]] and [[bleach]]. Generally, [[substance]]s exist as a [[solid]], a [[liquid]], or a [[gas]], and may change between these ''[[phase (matter)|phases of matter]]'' when there are changes in [[temperature]] or [[pressure]]. ==Gallery== <gallery> File:Silizium pulver.jpg|Gray [[silicon]] powder, an [[element]]. All the other ones are [[chemical compound]]s. File:Salt Crystals.JPG|White [[sodium chloride]] File:Manganese(II) chloride tetrahydrate.jpg|Pink hydrated (with water) manganese (II) chloride File:Manganese(II)-carbonate-sample.jpg|Brown manganese (II) carbonate File:CopperIIoxide.jpg|Black copper (II) oxide File:Cobalt(II)-chloride-hexahydrate-sample.jpg|Red hydrated (with water) cobalt (II) chloride File:Kaliumdichromat.JPG|Orange [[potassium dichromate]] File:Chroman sodný.JPG|Yellow [[sodium chromate]] File:Copper(II) chloride dihydrate.jpg|Green hydrated (with water) copper (II) chloride File:Copper sulfate.jpg|Blue hydrated (with water) copper(II) sulfate File:Chromium(III)-chloride-purple-anhydrous.jpg|Purple anhydrous (without water) chromium (III) chloride </gallery> == References == {{commonscat|Chemical substances}} <references /> == Related pages == *[[Chemical nomenclature]] {{chem-stub}} [[Category:Chemistry]]