00:01
Alright, so i don't recognize the alpha symbol that you have in there, but i assume that what you're looking for is a graph that has ph on the y -axis and has volume of titrant on the x -axis, because that's pretty standard for titration curves.
00:21
And we're trying to show carbonic acid dissociation.
00:24
In order to figure that out, you're going to need the ks for that.
00:27
So the ka1 for the first proton that's being dissociated is, when i looked it up, is 4 .5 times 10 to the negative 7th, and the ka2 for the second dissociation is 4 .7 times 10 to the negative 11th.
00:47
The reason why those are important is because the ph equals the pka at the half equivalence point of each of the two, and each proton is going to get its own curve.
01:04
So when you're sketching this out and you're just trying to show concentrations, because they want a species diagram for what's going on in each of the different parts, it's going to look kind of like this.
01:17
So there's the first acid being neutralized, here's the second acid being neutralized, and then there's the level off at the end.
01:24
At the very beginning, before anything has changed, you're going to have h2co3.
01:34
At this point right here, you're going to have half h2co3 and half hco3 -1, and that ph will be equal to the negative log of the ka of that 4 .5 times 10 to the negative 7th.
01:53
So i'll do that here real quick...