SOLUTION: A beaker contains 450 g of water (H2O). If 9.2 g of calcium fluoride (CaF2) is added, what is the molality concentration of the solution? (1 point) Select one: a. 0.020 m

Algebra ->  Circles -> SOLUTION: A beaker contains 450 g of water (H2O). If 9.2 g of calcium fluoride (CaF2) is added, what is the molality concentration of the solution? (1 point) Select one: a. 0.020 m      Log On


   

Question 824265: A beaker contains 450 g of water (H2O). If 9.2 g of calcium fluoride (CaF2) is added, what is the molality concentration of the solution? (1 point)

Select one:

a. 0.020 m
b. 0.26 m
c. 0.35 m
d. 4.8 m
Answer by josgarithmetic(39800) About Me  (Show Source):
You can put this solution on YOUR website!
Molality means moles of solute per kilogram of solvent.
Formula weight of CaF2 is 78.07 grams per mole.
Solubility of CaF2 at 20C is 0.0016 grams per 100 ml of solution.
This solubility is close to 0.0002 moles per kilogram water.

%289.2%2AgramsCaF2%29%2A%281%2Amole%2F%2878.07%2AgramsCaF2%29%29%2F%280.45%2Akg%2Awater%29
%289.2%2F78.07%29%281%2F0.45%29
highlight_green%280.26%29 moles CaF2 per kilogram water. This must certainly be wrong because the data in the question is faulty. You cannot have 0.26 m CaF2 if the solubility can only be 0.0002 m.