http://www.flickr.com/photos/77711474@N0…
look at this picture
see what i 've done in read.
why do we raise (3s) to the power of 3?
I know that OH is produced 3 times more than Al but isn't that what S an 3S show?
Why do we raise 3S to the power of 3?
look at this picture
see what i 've done in read.
why do we raise (3s) to the power of 3?
I know that OH is produced 3 times more than Al but isn't that what S an 3S show?
Why do we raise 3S to the power of 3?
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Coefficients in reaction equations become exponents in equilibrium constant expressions like the one for Ksp. There is a mistake on the page right before they plug in the variables. The general Ksp expression should be this:
Ksp = [Al 3+][OH -]^3
The 3 exponent comes from the fact that OH- in the reaction equation has a 3 coefficient. I know it seems like we're accounting for that coefficient twice (once in the 3s itself, and once again in the exponent), but each is the result of a separate part of the calculation. The S and 3S are showing that for every Al(OH)3 that dissociates, we get 1 Al 3+ and 3 OH-. The 3 exponent is a result of 3 coefficient in the reaction equation. Even if we had a buffer that kept the concentration of OH- constant even after adding Al(OH)3, that 3 exponent would still be present.
Ksp = [Al 3+][OH -]^3
The 3 exponent comes from the fact that OH- in the reaction equation has a 3 coefficient. I know it seems like we're accounting for that coefficient twice (once in the 3s itself, and once again in the exponent), but each is the result of a separate part of the calculation. The S and 3S are showing that for every Al(OH)3 that dissociates, we get 1 Al 3+ and 3 OH-. The 3 exponent is a result of 3 coefficient in the reaction equation. Even if we had a buffer that kept the concentration of OH- constant even after adding Al(OH)3, that 3 exponent would still be present.