 Okay, so let's try this one. What is the pH of 1.0 times 10 to the negative 3 molar KOH solution? So we know the concentration of KOH times 10 to the negative 3 molar. We also know what KOH does when we put it into water, right? So we can think of KOH, we can think of it as solid, putting it into water if we want, or we can start an aqueous, whatever. It breaks up into the K plus AQ and the hydroxide minus AQ. So what's the concentration of potassium miles then? Yeah, 1.0 times 10 to the negative 3, right? Because we went through what a lot of people like to call the mole, right? So we said moles here, right? It's a one to one ratio, right? So the moles must be the same here, okay? If it was a two to one ratio, it would be twice the amount, right? So, but it doesn't matter what the concentration of potassium ions are, right? It does matter what the concentration of hydroxide ions are. Why does it matter that? Yeah, you've got to find the POH, right? What are the two molecules that affect pH again? OH minus, right? H to H plus, okay? Those of you who aren't responding, you guys got to, we only got a little bit of time, you know? I want you guys to do well, okay? So out of these three molecules, out of these 30 particles, which one should we care the most about the concentration if we're looking for the pH, right? The OH minus, okay? So, OH minus is going to be the same concentration, 1.0 times 10 to the negative 3, molar, okay? We can figure out now, from there, we can figure out the POH if we wanted to, okay? We could also figure out the H plus concentration. We could do this a number of ways. We know KW, right? And we know, let's do it differently. Let's do it the KW. Well, we did the KWA last time, but we'll do both ways, okay? So H3O plus times OH minus, right? What is KW again? You guys remember? 1.0 times 10 to the negative 14, okay? So do you think we could figure out the H3O plus concentration? Yep, right? So H3O plus concentration equals KW divided by OH minus concentration. We got the OH minus concentration. We got the KW. 1.0 times 10 to the negative 14. Notice these units don't ever work, okay? So you got to just remember your units when we're doing any of this K equilibrium. So here, 1.0 times 10 to the negative 3. So what is it? 1.0 times 10 to the negative 11 molar, right? So is that the answer that we're looking for? No. No, because we're looking for the pH, right? That's the concentration of the molar. How do we do the pH? pH equals what? Negative. Negative log of that number, right? So what's the pH guys? Does this a different way? We could have done it the way that it wants us to do it up there, right? Let's do it that way instead. Can I erase all that stuff? And remember I recorded this. What we just learned are we just got lectured on how to do it. So instead of finding the pH, we could find the POH, which is very similar to finding the pH. POH equals what? Good job. Negative log of the POH. Concentration? Yes. Yeah, so this will mess up. Okay, so what is that? What other formula do we know? That the pKw equals the pH is the same number of stress groups. So we should be able to figure out what the pH is doing this way, right? So pH is going to be the pKw minus the POH. Is that right? That's 14.00. Is everybody cool with that? So what we're going to start off with is this, right? You don't know the chemical equation and you can't do any of this. Any questions on this? Pretty straight forward, right?