About: http://webisa.webdatacommons.org/271578250

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	Although it is not shown in the equation, chemicals, such as sodium hydroxide, are usually added to sodium sulfide solutions to help the sodium sulfide dissolve.
http://www.w3.org/ns/prov#wasQuotedFrom	sciencebuddies.org