00:01
In this problem we're told that we have 1 .0 molar formic acid.
00:04
We're told that we're going to take 100 milliliters, let me get my sig figs right on here, of formic acid, that's my abbreviation, and i've got a 1 point, my ka i looked up is 1 .8 times 10 to the minus 4, and we add naoh for a one -to -one buffer.
00:43
That means we have to add half the moles of hfo as naoh.
01:02
So i have 100 milliliters formic acid, it's 1 .0 millimoles per milliliter equals 100 millimoles, add 50 millimoles of naoh.
01:34
So i'm going to have this f hfo plus oh minus yields minus plus o.
01:45
I start with 100, i start with 50 and zero.
01:52
So this will go minus 50, minus 50, and plus 50, i get zero, 50, and 50.
02:01
Now we're going to add hcl to our buffer.
02:04
Add 30 milliliters of 0 .10 or 1 .00 molar, which is 0 point, or that's 30 millimoles.
02:43
So we've got our f minus plus hcl and that will make hf and h2o plus cl.
03:03
So i have 50, 50, and i add 30...