yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

2015 AP Chemistry free response 3e | Chemistry | Khan Academy


2m read
·Nov 11, 2024

The initial pH and the equivalence point are plotted on the graph below. Accurately sketch the titration curve on the graph below. Mark the position of the half equivalence point on the curve with an X.

All right, so we have— they show us the initial pH right over here, and they also show us the equivalence point right over here. At the pH of— we actually saw that in the last problem with the equivalence. The equivalence point was measured; the pH at the equivalence point was measured to be 2.54. So that's why this right over here is at 2.54.

When we've added about 29 point—I forgot what the number was. It was in the— it was in, I think, the second part of this problem. They said when you added close to 30 milliliters of that hydrochloric acid, of that 1.25 molar hydrochloric acid solution, that is when we hit our equivalence point, and we see the pH right over there.

And then the half equivalence point— well, that's going to be when we've added half this amount. So it's going to be a little bit less than 15. In the last problem, we figured out that that was going to be a pH of 4.77. So a pH of 4.77 is going to be something like right over there. They said to mark that with an X. So the half equivalence point— we've added half the titrant there, and we know the pH. We figured that out in the last part of the problem.

Now we just need to graph— we need to sketch the titration curve. So let's see. We keep adding more and more hydrochloric acid. Hydrochloric acid lowers the pH. We get to the half equivalence point, and then actually we're going to start leveling off over here. The reason why you level off is because you're going to have more and more of the conjugate acid there.

As you react with the conjugate base, with more and more of the conjugate base, the equilibrium between the conjugate base and the conjugate acid— more of that acid is going to go to conjugate base, so you're going to have a little bit of buffering going on. But at some point, you have completely reacted with everything, and you hit your equivalence point. You hit your equivalence point, and then you've become much more acidic.

It might look something— it might look something like that. Let me see if I can do a little bit better, a little bit better job. So it would look something— and we're obviously— it's not going to be exactly right. It's important we go through these three points, and it would look something like that. So that's the equivalence point, half equivalence point, and then this is our initial pH.

More Articles

View All
Your Whole Goal Is to Not Quit - Courtland Allen of Indie Hackers
But yeah, why did you decide to start doing a podcast after the site was going? People were asking for it. It seemed like a good idea. I mean, the number of people who asked me to do a podcast was so much higher than people who asked for any other featur…
INSANE Watches Inspired By Firefighters
So we actually make the watches, Kevin, from genuine upcycled firefighting materials. So even the case itself has 100 years of real firefighting history, we say, beating through every component. This is a wonderful here, Geneva, Switzerland, with Johnny G…
Solar and lunar eclipses
In a previous video, we asked ourselves a very important question. As the moon has its 28-day cycle around the Earth, we talked about how a new moon is when the moon is between the Earth and the Sun. From the Earth’s point of view, or from the point of vi…
Advanced (plural) possession | The Apostrophe | Punctuation | Khan Academy
Hello Garans, hello David, hello Paige. So today we’re going to talk about plural possession, meaning when more than one person, or thing, or animal owns something else. This, like most other types of possession, tends to involve apostrophes. Makes sens…
Kevin O'Leary: 40 Years of Photography
Amateur shutterbug since the 70s, now he’s selling his prints and giving the proceeds to help young Canadian entrepreneurs. Earlier today, he walked me through his exhibit, “40 Years of Photography.” It’s at First Canadian Place here in Toronto. So here’s…
15 Ways to Increase Your Income This Year
You need more money because everything’s become extremely expensive. It doesn’t matter if you’re an employee, a freelancer, or a business owner. Here are 15 ways to increase your income this year. First up, brute force. Work more hours if you’re able to …