<p>how do you get a pK(sub a) of 4.7 from K(sub a) of 1.8X10^-5? I know that -log of 1.8X10^-5 equals 4.7 from my calculator, but how would you find it without a calculator?? </p>
<p>P.S> I hate buffersss oh and the chem sat II is extremly difficult pour moi, ugh, so any help out there???</p>
<p>you won't have to do calculations like that on the SAT. if there is a question like that, they are going to have answer choices that are like 4.7, 10, 2.4..etc etc, but from estimation, you know its around 5, so you pick the answer choice nearest to 5.</p>
<p>I really doubt they'll give questions like that. I didnt get any.</p>