washes = lava - to clean with water (the object gets soaking wet)
cleans = limpa - to clean (may use small amounts of water, but not soaking wet)
The distinction in english isn't parallel to portuguese, then? If you're sweeping or vacuuming, you'd probably say precisely that, and if you're "cleaning," you're probably mopping (also reasonably referred to as washing).
What is the difference between "Chao" and "Andar"? Both translate to "floor" in English
Chão is only about the floor, the pavement where you step on; it can also mean the "ground". Andar, in this case, would be the floors you have in a building. 1st floor = 1o (primeiro) andar etc.
Chão is under the things, where we walk, keep the furniture and so on. Andar is "walking", also "a 2-story house" (uma casa de dois andares)
I think you can use either in this sentence, but the meaning would change. Ela limpa o chão = She cleans the floor (of the house, the office, etc.). Ela limpa o andar = She cleans the floor (all the hotel rooms on the 3rd floor). Can a native speaker confirm this?
I am not a native speaker, but when I hear this sentence, I think of cleaning inside a building. I suppose someone might choose to clean the pavement outside (road, sidewalk), but that would be less common. However, I have seen shopkeepers with open-air shops sweep or wash the sidewalk in front of their store, so it might be OK. Can a native speaker comment on this?
Why "She cleans up the ground" is not accepted? O.o