Chemistry
posted by Sam .
Find the Concentration of CrO4^2 in 0.0033M Ba(NO3)2 saturated with BaCrO4. Include activity coefficients in your solubilityproduct expression. Ksp of BaCrO4 = 1.17 x 10^10
I have no idea what to do to solve this :(

Calculate ionic strength of 0.0033M Ba(NO3)2. Then calculate activity coefficient (or some books have a table that can be used).
Then [(Ba^2+)*fBa] x [(CrO4^2)*fCrO4] = Ksp = 1.17E10
Substitute (Ba^2+) = 0.0033M + x
for (CrO4^2) substitute x
Substitute fBa and fCrO4 and solve for x. 
Thank you for answering! I got .0099 for the ionic strength. I just don't understand how to calculate the activity coefficient though. We just learned the concept and I'm confused.