Hey, guys, In this new video, we're gonna take our first looks at what exactly is a buffer and how do exactly do they work? So we're gonna say here solutions that contain a weak acid and its conjugate base. Remember when I say weak acid, we could think of HF conjugate base means it has one less h plus. So take off the H plus you have f minus. But professors don't like to give you just f minus. They'll combine that F minus with a metal So we could say our conjugate base here is n A F. So solutions which contain a weak acid like HF and a continent base, has one less h like N A F R called buffer solutions because they resist drastic changes in ph. Now, how do they accomplish this? Well, they do this by keeping your H plus concentration and your O. H minus concentration constant. It keeps them basically the same. The way this works is we're gonna say, adding a small amount off strong base and the pH will increase because remember, if you add base, you're gonna go above seven, so you keep going up and up. But It's not gonna increase by much because the weak acid will neutralize the strong base that you that you add now adding a small amount of strong acid and the pH will decrease again. It's not gonna decrease by much, because why the conjugate base will neutralize what you add. So that's how buffer works. Any acid or base that I add. They get reacted with either the weak acid or the conjugate base. So remember, accident bases are natural enemies of each other. So if I add base, my weak acid steps in to try to take it out. If I add acid, my conjugate base steps up and tries to take it out. That's how a buffer will work. Remember, the only things that could destroy a buffer is by adding too much strong base or too much strong acid. Adding water to a base does nothing to it, well, adding water to not a base, but a buffer does nothing to it. Why? Because adding water would change the concentration of my weak acid. But it also change the concentration of my week based proportionately so proportionately the ratio would stay the same, so my buffer would be unaffected by the addition of water. So remember, adding a strong acid or base is the only way to really destroy buffer. Adding water does nothing to it. Now, knowing this, I want you guys to try to answer this first practice question. We're gonna say which one of the following combinations does not create a buffer. Remember, we just set up above Ah, buffer is a weak acid and it's conjugal base. So this is gonna require you guys to remember the rules that we talked about and identifying compounds and either being acidic or basic, strong or weak. Once you can do that, you'll be able to guide your way to the correct answer for this one. Come back, click on the explanation button and see the choice that I make and see if it matches up with yours.

Hey, guys, In this new video, we're gonna take a look at what are the different ways to create a buffer? All right, we know what a buffer is. A buffer is made up of a weak acid and conjugate base or a conjugate acid and a weak base. So that's what a buffer is. But there are three ways to make a buffer. It's gonna be important that you guys recognize these three ways. Now we're gonna say the first way is obvious. Ah, buffer is made up of a weak acid and it's consequent base. So one way to make a buffer is just mixing those two things together. So we're gonna say, mixing a weak acid and its conjugate base. So, for example, what we need to realize here is that we're gonna say in this case, Ah, good buffer, an ideal buffer. So ideal buffer means that this is the best type of buffer. An ideal buffer is when our weak acid equals r conjugate base there the same amount. So let's say we have 0.1 Mueller HF and 0.1 Moeller and A F, and we should realize that the numbers could be different for them, but they work best when they're the same. We're gonna say this has to do with our buffer range. What you should realize here, a good buffer has to fall within the range of 10 to or 1 to 10. Okay. So what do I mean by that? I mean this. So 10 toe one that means are weak. Acid at most could only be 10 times more than my conjugate base. If it falls without that outside that range, it'll be a bad buffer. Okay, so good buffers between 10 toe attend to one ratio or 1 to 10 ratio. And the 1 to 10 now, the weak acid is one, and the conjugate base is 10 times that. Okay, So, again, this is the buffer range. Ah, good. Buffer falls within this range. If it falls outside that range, it'll still be a buffer. It'll just be a very bad buffer. And remember, an ideal buffer is the best buffer. That's when both are the same. Now, connected to this also is another topic which is called our buffer capacity. Now we're gonna say buffer capacity. All it means is the more concentrated my weak acid and conjugate base, the better my buffer. And this makes sense because remember, what is a buffer doing? It's trying to neutralize the strong acid in the strong base that you add to them, and they can't do their job effectively if there's a little bit off them. So to fight such strong acids and strong bases, you need a lot of weak acid and a lot of conjugate base. The more the better, the more they can better defend themselves. So here we're gonna say, this is good because they're both the same number. But this is better because it's more concentrated. So this has a better buffer capacity. Oops. Okay, so buffer capacity, the more concentrated the better. Now, if we go back to this ideal buffer, we're gonna say that's when they both equal each other. We're gonna say that this is found at our half equivalents point when we reached the half equivalents point. That's when we have an ideal buffer. We'll talk more detail on that when we get to titrate Asian graphs. When we get to the Thai tray shin graphs of buffers, we'll take a close look and see what do I mean by the half equivalents point. And why is this an ideal buffer? So just for right now, write a little note on that and ideal buffers when they're both equal. This happens at the half equivalents point. So remember the difference between buffer capacity and buffer range, uh, the best buffers when they're both equal in amount. The buffer rain says there could be a 10 to 1 ratio. Once it's outside that 10 to 1 ratio. The buffer is still a buffer, but it's gonna be a bad buffer. It'll get destroyed very quickly by a strong acid or base that we add.

Now, the second way to make a buffer is to mix some strong acid with some weak base. But here's the thing about this type we're gonna say here the week base has to be higher in amount. Must be hiring amount. If the weak base is equal to the strong acid, it will destroy the buffer. If the strong acid is greater than my weak base, it will destroy the buffer. Okay, so the week base has to always be higher than the strong acid. Otherwise, the buffer will be destroyed. So if we take a look at an example, we can say Here we have one mole of HF and 1.5 moles off NH three and actuaries are weak base and there's more of it. Our units here could be moles or mole Arat E. In this case, this would be a buffer if we have one mole of HF and one more of NH three no longer a buffer because the strong species is equal to my week Species, if I have one point Not sorry, this is HCL. Actually H f is a weak acid. So disregard that hcl if I have one more 1.5 moles of HCL and still one more off and H three. This would also no longer be a buffer. Your strong species cannot be equal to or greater than your week species. If it is, your buffer gets destroyed. So remember that the week species has to be higher in amount in the strong species.

And then finally the last type. We just said strong acid in week base. So let's reverse it. Weak acid and strong base. So example here we could have one point. Let's do different. Number 250 Mueller HF. Now that's a weak acid and 1.0 Mueller N a O h. Okay, so now are weak. Acid is definitely larger, an amount so again here we need the week species higher in amount. So this would be a buffer. Got to remember that. So if we go back, first way is to mix weak acid and contacted base here. They could be equal to or differ from each other. But the good buffers are within the range of 10 to 1 in the next to the week. Species has to be higher than the strong species. Otherwise, it won't be a buffer. You have to remember all three cases because you'll be tested on them. And if you don't know which is which, you won't be able to get the correct answer. So just remember we cast the contact base that could be equal. It could be different asl, long as it's within the range of 10 to 1. It's a good buffer. If it's outside that range, it's a bad buffer. Case two and three the week Species have to be higher than the strong species. The strong species cannot be equal to or greater. If it is, the buffer gets destroyed. Remember these principles and the help guide you to see if you have a buffer or not.