joeeeey3 Full Member 10+ Year Member Aug 7, 2012 #1 Advertisement - Members don't see this ad using common ion effect, i got 4.2 x 10^-14 but the answer key says its 4.2 x 10^-6 and it doesnt even show solution. is this an error? Attachments chadsss.gif chadsss.gif 27.4 KB · Views: 94
Advertisement - Members don't see this ad using common ion effect, i got 4.2 x 10^-14 but the answer key says its 4.2 x 10^-6 and it doesnt even show solution. is this an error?
C cj7 Full Member 10+ Year Member Aug 7, 2012 #2 4.2 X 10^-6 is correct. ScF3 --> Sc + 3F- ksp = [Sc][F-]^3 [Sc] = x [F-] 3x + .0001, but 3x is negligible, so [F-] = .0001 now plug into ksp equation: 4.2X10^-18 = (x) (.0001)^3 X= 4.2 X 10^-6 M Upvote 0 Downvote
4.2 X 10^-6 is correct. ScF3 --> Sc + 3F- ksp = [Sc][F-]^3 [Sc] = x [F-] 3x + .0001, but 3x is negligible, so [F-] = .0001 now plug into ksp equation: 4.2X10^-18 = (x) (.0001)^3 X= 4.2 X 10^-6 M
J jaymin8 Full Member 10+ Year Member Aug 7, 2012 #3 ScF3 So that is Ksp= [Sc][F]^3 Given: [F] and Ksp SO.... 4.2*10^-18= [Sc] [1.0*10^-4]^3 -----> multiply exponents 4.2*10^-18= [Sc] [1.0*10^-12] -------> when dividing, you subtract exponents. Sc=4.2*10^-6 Upvote 0 Downvote
ScF3 So that is Ksp= [Sc][F]^3 Given: [F] and Ksp SO.... 4.2*10^-18= [Sc] [1.0*10^-4]^3 -----> multiply exponents 4.2*10^-18= [Sc] [1.0*10^-12] -------> when dividing, you subtract exponents. Sc=4.2*10^-6
