량, 양 both refers to the accountable or measurable one. When it is used as independently, only 양 is used. ex) 양이 많다, 양이 적다. When it used after a noun, 량 is used after Sino-Korean word and 양 is used after pure Korean word or a loanword ex) 양: 구름양, 알칼리양. 량: 가사량, 노동량, 작업량