CaSO4 --> Ca^+2 + SO4^=
Ksp = (Ca^+2)(SO4^=)
Substitute 0.02M for (Ca^+2) and calculate (SO4^=) needed to cause ppt of CaSO4.
That will be in M; therefore, for 1 L of solution that will be the moles.
Then grams Na2SO4 = moles x molar mass Na2SO4.
How many grams of solid sodium sulfate can be added to 1000L of a 0.02mol/L solution of calcium chloride before a precipitate forms? (Ksp for calcium is 6.1x10^-5)
3 answers
But why 1L of the solution? Why not use the 1000L?
Because I am so used to working problems with 1 L that I just read 1 L into it. Excuse me please.
You are right. After you know the concn of SO4 needed to ppt CaSO4 (in 1 L), then multiply that by molar mass Na2SO4 to find grams for 1 L, then multiply by 1000 to obtain grams Na2SO4 for 1000 L.
You are right. After you know the concn of SO4 needed to ppt CaSO4 (in 1 L), then multiply that by molar mass Na2SO4 to find grams for 1 L, then multiply by 1000 to obtain grams Na2SO4 for 1000 L.