volatile

evaporating readily at normal temperatures and pressures; "volatile oils"; "volatile solvents"

liable to lead to sudden change or violence; "an explosive issue"; "a volatile situation with troops and rioters eager for a confrontation"

marked by erratic changeableness in affections or attachments; "fickle friends"; "a flirt''s volatile affections"

tending to vary often or widely; "volatile stocks"; "volatile emotions"

a volatile substance; a substance that changes readily from solid or liquid to a vapor; "it was heated to evaporate the volatiles"