About: http://webisa.webdatacommons.org/91833509

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Wikipedia draws a definition from the Compendium of Chemical Terminology: In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com