00:01
Okay, here we're mixing 100 mil liters of .2 molar k -o -h and 200 milliliters of .15 molar niso4.
00:08
And we get this reaction here.
00:10
You know, it wants this to find which one of these species, which one of these two species go ahead and precipitate, which one, which one of these reactions is limiting, and then the concentrations of the aqueous ions and the grams of the solid precipitate.
00:26
So, let's identify which one of these is going to precipitate.
00:32
So kind of the rule of thumb is anything with potassium in it, or also in the future, n .a.
00:41
Plus.
00:43
Sodium.
00:44
N .a.
00:45
Plus, yeah.
00:46
And it's going to precipitate out.
00:50
It's going to, sorry, it's going to stay soluble.
00:52
So potassium, sodium, almost always soluble.
01:03
Sulfate also commonly soluble.
01:09
So this is going to be most likely soluble.
01:13
Hydroxide, when often insoluble, when with metal.
01:25
So iron hydroxide also crashes out, and so nickel hydroxide here is going to be as precipitate.
01:31
And that's going to kind of be a common rule of them, is usually your metal ion is the one that's going to crash out.
01:38
And so then this will stay aqueous.
01:41
So here's going to be our precipitate, and here is going to be our aqueous product.
01:46
So now let's find which one's limiting.
01:47
In order to do that, we need to know how much of this, of each of these we have.
01:53
And so let's find how many moles of k -o -h.
01:55
We're going to take, well, first, molarity is moles per liter.
02:00
So let's take moles per liter, and let's convert this into liters.
02:05
So we're going to divide this by 1 ,000, to get 1 ,000.
02:08
Liters and so we have 0 .1000 liters.
02:13
And then we're multiply that by our concentration of 0 .2 .00 moles per liter.
02:18
Leaders cancel and we're left with 0 .2 00 moles.
02:33
I'm going to raise this so that i just, you know, hydroxyl with metals often soluble.
02:38
I need space to write this though.
02:41
So again, divide this by a thousand and we get 0 .2 000 liters times 0 .150 moles per liter, 0 .0 .0 .0.
03:00
Let's put them in.
03:02
Watch right here.
03:09
One too many zeros.
03:11
3 .0 .0 .0.
03:13
All right.
03:14
So you can see here, we're using potassium hydroxide twice as fast as we are nickel sulfate, but we have less of it.
03:20
So this is going to be our limiting reagent.
03:24
And so with the that knowledge, we can now react to this one to 0, subtract it from this column, but we have to adjust it for the stochemetric coefficient, right? for every two of these, we use we use one of these, so we're going to multiply this by one -half, and then we're added to our product side, but again we need to adjust for one -half the stochimetric coefficients of these species here.
03:59
So this ends up 0 .02 -00, but this becomes 0 .10...