I have asked this question before but I was wondering if I solved this question correctly.
A solution of barium chromate is prepared by dissolving 6.3 x 10-3 g of this yellow solid in 1.00 L of hot water. Will solid barium chromate precipitate upon cooling to 25°C?
You want to compare Qsp to Ksp (at 25o C.)
BaCrO4 (s) ==> Ba + CrO4
Ksp = BaCrO4= 1.17×10-10
6.3E-3g/253.33molar mass BaCrO4 = 2.49 x 10-5 mols BaCrO4 in 1
Qsp = (x)(x) = 6.18 x10-10
I feel that I did something wrong (the answer to my question before included silver chromate not barium chromate, hence my confusion)
You haven't answered the question. Will BaCrO4 ppt upon cooling?
You haven't done anything wrong. All of the numbers look good to me. You just need the conclusion. OR tell us what you are confused about.
Another way of solving the problem is to calculate the solubility of BaCrO4 at 25 degrees C from Ksp and compare that molar solubility with the initial hot water molar solubility OR change the molar solubility of BaCrO4 to grams and compare directly with grams BaCrO4 dissolved in the hot water.
To determine whether solid barium chromate (BaCrO4) will precipitate upon cooling to 25°C, you need to compare the calculated ion product, Qsp, to the solubility product constant, Ksp. From the information you provided, the Ksp for BaCrO4 at 25°C is given as 1.17×10-10.
You correctly calculated the amount of BaCrO4 dissolved in 1.00 L of hot water to be 2.49 x 10-5 moles. This value represents the initial concentration of BaCrO4 in solution before cooling.
To calculate Qsp, you need to square the concentration of BaCrO4 because in the balanced equation, one mole of BaCrO4 produces one mole of Ba2+ and one mole of CrO42-. Therefore, Qsp = (x)(x) = 2.49 x 10-5 x 2.49 x 10-5 = 6.18 x 10-10.
Comparing Qsp to Ksp, you find that Qsp (6.18 x 10-10) is greater than Ksp (1.17×10-10). According to the principles of solubility, if Qsp is greater than Ksp, a precipitate will form. Therefore, solid barium chromate will indeed precipitate upon cooling to 25°C.
Your calculations appear to be correct, and you have reached the correct conclusion based on the given information. Well done!