[krees]

I have 0.01M acetic acid, o.1% (w/v) purified casein in 0.1M sodium acetate in samples A, B, C.

Sample A contains 0.60ml acid, 8.4ml water and 1ml base.
Sample B contains 1.25ml acid, 7.75ml water and 1ml base.
Sample C contains 2.5ml acid, 8.5ml water and 1ml base.

i've calculated them and they've all come back with a pH of 14.76

what am i doing wrong?

[Babcock_Hall]

Are you accounting for dilution of your stock solutions?

[Borek]

i've calculated them and they've all come back with a pH of 14.76

what am i doing wrong?

And how are we going to guess what and how you are calculating, to tell you were is the mistake?

[krees]

for sample A, I did:-

pH = 4.76 +log10 (0.1/0.01) = 14.76

I forgot to say that the pKa = 4.76

[Babcock_Hall]

One, I think it is crucially important to distinguish the concentrations of stock solutions from the final concentrations of the chemical species.  You will need to do some dilution calculations, if I am not mistaken.  I don't think you are doing that.  Two, you are not calculating your logarithms correctly.  log₁₀(10) = 1, not 10.

[krees]

ok, i figured out the log thing, but the dilutions i am unsure of, i've divided 8.4 by 0.6 and got 14.  then i divided the concentration of the acid by 14 and put that into the equation and got a pH of 6.9. does this sound better?

[Borek]

No. What are you trying to calculate by dividing 8.4 by 0.6?

Correct approach is to calculate how much acid is present and then to divide by the total volume. Total volume is approximately sum of all volumes mixed.