| MadSci Network: Chemistry |
Yes to the first, "not necessarily" to the second question.
The Law of Conservation of Mass is one of the main reasons we know anything in chemistry, and it says that you are guaranteed to end up with the same amount of water and salt you started with, less mechanical losses (leaky glassware, splashes and spills, and so forth).
On the other hand, "one grain" of salt is a highly variable quantity; salt crystals have all different sizes. Unless you're talking about the unit of weight/mass: 1 grain = 64.8 milligrams (or exactly 5/100 of a scruple).
Dan Berger
Try the links in the MadSci Library for more information on Chemistry.