00:02
Hi there, in this question we are given the molarity of the ionic compound and we want to know the concentration of the positive ion or the cation and the anion in each one, assuming that they dissociate completely.
00:16
So let's start with letter a.
00:18
In letter a we have sodium sulfate, na2so4.
00:25
So when this dissociates, what we're going to get are two sodium ions and one sulfate ion, which is our anion because it's the negative ion.
00:52
And we're told the original concentration is 0 .12 molar.
00:58
Well, if we get two sodium ions, we're going to have double the concentration of the sodium ions.
01:09
So two times 0 .12 molar is going to be 0 .24 molar.
01:15
For the sulfate, looking at the coefficient, it's just a one, so we have a one to one relationship.
01:22
So the sulfate, the negative ion, the anion, is simply going to be 0 .12 molar.
01:31
And again, this one's the cation and this one is the anion.
01:38
All right, let's go ahead and repeat this for letter b.
01:42
The first thing we want to do is to write the dissociation equation.
01:48
So in letter b we have potassium carbonate.
01:52
Potassium is k, carbonate is the polyatomic ion, co3.
02:01
Therefore, when this dissociates, we get two potassium ions for every one carbonate ion...