multiplying a log by negative one--flip?

[SaintJude]

TPRH (p.477)-passage 69 no. 2

When they multiplied the log by negative 1, they seemed to make a flip of the log. Is this correct? The point was to convert the Henderson-Hasselbach equation into its non-log format.

---

Members don't see this ad.

 

[UrshumMurshum]

Whatever you multiple the logarithm by it's the same as exponentiating the argument (what's in the parenthesis) by the same value.

so for instance

a - log(a/b) = a + (-1)log(a/b) = a + log([a/b]^-1) = a + log(b/a)

Because [a/b]^-1 = 1/[a/b] = b/a

 

[chiddler]

 

[SaintJude]

Riiight. Oops--Well, anyway, I like that version of H-H equation much better.

[H+] = Ka x [acid/base]

 

[Morsetlis]

it's best to remember one version for the rest of your life, and conjugate the others on the spot.

I use as few negatives as possible.

pK = pH - log a-/ha
pH = pK + log a-/ha

Haha!
aha!