I don't know what your answers were but the more "stuff" there is the more energy it takes to freeze or boil it. Hope this could help
Covalent
A covalent bond is the bond where electrons are shared. This occurs between two non mental. N is nitrogen and O is oxygen, therefore NO would be a bond between two non metals. So it must be covalent.
No, why? Cause if you're winding up the clock it's basically doing what it needs to do. So there's no need for batteries.. I hope my sad sentence make sense :p
