booo! I was starting to like the reaction equation - it solved EVERYTHING! lol
so how's this for a start:
pH = pKa + log[conj. base] / [acid]
5.0 = 4.74 + log x / 0.1
5.0 = 4.74 + log(x) - log(0.1)
0.2553 = log(x) - 1
1.2553 = log(x)
10^1.2553 = x
x=18.001
so 18 is the concenntration of my conjugate base?
that seems a little high... lol
and then for my [H+],
[H+] = Ka[HA]/[A-]
[H+] = (1.8*E-5(0.1)/(18)
[h+] = 1.01e-7
TINY NUMBER lol - this doesn't look right to me.