What is {density} of {brass} that is {phase of matter} is {solid} ?
When in a solid state, what is the density of brass?
What is the density of brass when it is a solid?
SELECT ?d WHERE { resource:brass property:density ?g . ?g property:density ?d . ?g property:phase_of_matter resource:solid }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q39782> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2054> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P515> <http://wikidata.dbpedia.org/resource/Q11438>
} 

SELECT ?obj WHERE { wd:Q39782 p:P2054 ?s . ?s ps:P2054 ?obj . ?s pq:P515 wd:Q11438 }