iTutor Chemistry Updates

So I have been going over organic reactions. I just wanted to be clear if I understand the Sn2 mechanism. So it occurs when you introduce a better nucleophile to a compund with a not so good nucleophile but good leaving group. For example, if you were to put, let's say, bromoethane into water, would the water break off into a hydroxyl group and replace the bromine and give it a hydrogen making ethanol and hydrobromic acid?