00:01
Hey there.
00:01
Today we're trying to figure out what the ph is and wants to change phs of this problem that they're giving to us.
00:07
So basically you have buffer a, which contains 0 .01 mole of lactic acid, which has a pca of 3 .86.
00:18
And then you're going to have 0 .05 moles of sodium lactate.
00:26
And we're going to calculate the ph.
00:28
And then we're going to calculate the change when we change the ph from.
00:31
5 milliliters of 0 .5 molars, and we're going to add it with 1 liter to the buffer.
00:38
Okay? so i just kind of wrote out what our goals are, which is with a and b, and now we're going to actually do the work.
00:45
This isn't too difficult, but you do need a calculator.
00:49
Can't do logs in your head.
00:52
Poor decision.
00:54
Okay, let's start out with a.
00:56
So we have a ph.
00:57
No ph equals 3 .86, right? that's a pk plus the log of 0 .050 over 0 .0 .1, which equals, all let's all do it on our calculators.
01:27
4 .56.
01:30
That wasn't too bad, was it? okay, so that's the answer to a.
01:37
See, look at you.
01:38
You're already a biochemistry's not that fun.
01:43
But biology, it's an unique chemistry for biology.
01:48
So moles, h plus added, we know that equals 5 times 10 to the negative 3rd liters times 0 .5 molars.
02:20
We got all that information from our question.
02:29
All right, so sorry, i couldn't find a word for questions.
02:32
So let's put this in our calculators...