Is there a difference between these two questions?
I believe with どこにデパートがありますか the speaker is essentially asking “Where is a department store (around here)?”. There is no certainty whether there is one or not. デパートはどこですか, on the other hand, has the nuance of “where is the department store?”. The speaker knows that one exists but doesn’t know its location.
Since Lucas prefaced his reply with “I believe”, I’ll just jump in here to confirm he’s right. When I asked a native, she gave pretty much the same exact answer Lucas gave.
It makes sense when you think about it, though. デパートがあります uses が to mark ある as a sort of property of a department store and then calls into question where it is with どこに and か. Essentially it asks “where is it that a department store exists”, which is why it lacks some of that certainty.
Yes, basically the difference is
"is there a store here?“
"where is the store?”
It’s quite embarrassing (and mind blowing) that I’ve been studying Japanese for over 2 years now and I never knew that difference existed. Thanks!
It is really logical and obvious now that I think about it. I guess I just always accepted that they had almost no difference in nuance .
Really the key is the properties of が and は. We’re all learning new things and sometimes things we think we should already know. I have that feeling on a daily basis, so you’re not alone. I’m just glad the explanation makes sense.
Thanks a lot! You made it very clear!