Question
If 2.00 mL of 0.600 M NaOH are added to 1.000 L of 0.850 M CaCl2, what is the value of the reaction quotient and will precipitation occur?
I've been trying this problem over and over and haven't been able to get it. I know precipitation will not occur from my previous answer and that part was correct but not my reaction quotient.
I've been trying this problem over and over and haven't been able to get it. I know precipitation will not occur from my previous answer and that part was correct but not my reaction quotient.
Answers
DrBob222
Why don't you post your work and let us find the error.
Rachelle
Ksp for Ca(OH)2 is 5.02 x 10^-8.
The way to predict whether a precipitation will occur is to calculate Qsp and compare to Ksp.
Qsp = (Ca2+)(OH-)^2. Concentration of OH- will be given by (M1V1/V2) = 0.0012
Qsp = 0.850 * (.0012)^2 = 1.22*10^-6
My homework says this is not correct...
The way to predict whether a precipitation will occur is to calculate Qsp and compare to Ksp.
Qsp = (Ca2+)(OH-)^2. Concentration of OH- will be given by (M1V1/V2) = 0.0012
Qsp = 0.850 * (.0012)^2 = 1.22*10^-6
My homework says this is not correct...
DrBob222
I don' see anything wrong with this. I calculated OH using 0.6 x 0.002/1.002 and came up with a slightly smaller number but it rounds to your value and if I square that and multiply by Ca (I used 0.850 x 1/1.002) = 0.848 but no matter how I slice it the answer always rounds to 1.22E-6. If the only thing you are keying in is the answer of 1.22E-6 then I think the database must be wrong. Do they want unit? Technically there are no units although I see a lot of prof using them.