Actually it is very uncommon to say "O quarto é vazio" in Portuguese, it doesn't make much sense to talk about a room that is empty by nature. If it were the inverse translation I would definitely say "o quarto está vazio".
I've seen Duolingo mistakenly putting "é" instead of "está" a few times already. It's not completely wrong, but it changes a meaning to an extent that it becomes a weird sentence.
One can say «quarto de cama» for "bedroom," but we normally just shorten it to «quarto» in everyday speech. It becomes extremely easy to know that one is referring to a bedroom when you use a possessive, too: «no meu quarto...» = "in my bedroom...." Obviously, in English you can say "my room," and you do not have to specify "my bedroom," either.