posted by Hannah .
Calculate the concentration of HCO3- in an aqueous solution of 0.0885 M carbonic acid, H2CO3 (aq).
I was going to set this up as 0.0885 -x = ? Am I suppose to use the Ka value for carbonic acid?
Yes, k1 for carbonic acid.
0.0885 - x = 4.2e-7
Then I added 0.0885 to the right side and got 8.85e-2. Would this be the concentration or do I need to do another step?
You need another step.
H2CO3 --> H^+ + HCO3^-
k1 = (H^+)(HCO3^-)/(H2CO3)