00:01
Remember that buffers are most effective when the ph equals the p -k -a.
00:08
That means if we're finding, if we're looking for a buffer to use for a solution that has a certain ph, we can try to find a buffer that has a similar p -k -a to that ph.
00:23
This also means that the ph is equal to the negative log of the k -a.
00:31
Or k -a is 10 to the negative ph.
00:39
So if we have a ph of 4 .5, then 10 to the negative 4 .5 is 3 .16 times 10 to the negative negative 5.
00:55
So this is the k -a that we're looking for for a weak acid or weak base.
01:05
Ethanolamine, or h -o -c -h -2, ch2, nh2, has a k -a value of 3 .2 times 10 to negative fifth, and a conjugate acid of h -o -c -h -2, ch2, nh3 plus.
01:34
Adipic acid, or h -o -o -c -h -2, c -h -2, c -h -2, and h -dic2, 4 c .o .o .o .h.
01:44
Has a conjugate base of h .o .c.
01:48
C .h .2 for c .o...