How many {mass} are for {potassium ferricyanide} ?
What is the molecular weight of potassium ferricyanide?
How much is the mass of potassium ferricyanide?
SELECT ( COUNT ( ?l ) AS ?x ) { resource:potassium_ferricyanide property:mass ?l }
SELECT (COUNT(?obj) AS ?objs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q408810> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2067> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
} 

SELECT (COUNT(?obj) AS ?value ) { wd:Q408810 wdt:P2067 ?obj }
2