KAPLAN DAT Diagnostic GCHEM #56

[syko]

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Hi guys
Someone please help me with this question on kaplan dat test. The question is CaF2 is added to 0.1M of Ca(NO3)2. what conc of F will CaF2 precipitate? Ksp of CaF2 = 4* 10^-11

I set up the equation as (0.1M) (2x)^2 = 4* 10^-11. The answer says it's suppose to be (0.1M) (x)^2 = 4* 10^-11. Im a little confuse on when you suppose to add the number of molecule inside the ( ). thanks in advance

 

[Kahr]

This has been asked about earlier here:

http://forums.studentdoctor.net/showthread.php?t=888706

and here:

http://forums.studentdoctor.net/showthread.php?t=801375 🙂laugh: I actually tried to answer this one, didn't remember that I had)

Hopefully one of those helps, there was also another one, but I'm hoping the two above will be enough. Just a suggestion since you're new to the forum (at least I assume you are), do a quick search to see if someone else has had trouble with a problem first, you might find your answer faster. 🙂