What is the chemical formula of the neutral compound formed from...?

Question

What is the chemical formula of the neutral compound formed from:
(Cu)^2+ ions and (NO3)^1- ions.

and

(Ba)^2+ ions and (SO4)^2- ions.

and please explain...

Answer 1

Cu+2 + 2 NO3- ====> Cu(NO3)2


Ba +2 + SO4-2 ===> BaSO4

This is easy -- allyou have to do is add up the number of + charges, and match it with an equal number of - charges.

Cu+2 (cupric ion) has a positive 2 charge, NO3-1 (nitrate ion) has a negative 1 charge, so to make a neutral compound, you need two nitrates for every cupric.

Ba+2 (barium ion) has a +2, SO4-2 (sulfate ion) has a negative two, so a one:one ratio will work: BaSO4