Question #06b85

1 Answer
Slangus
Nov 18, 2015

19.99 g CaCl

Explanation:

This is a dilution problem. The equation for dilution is:
(M_1)(V_1)=(M_2)(V_1)

You're given the mass of calcium chloride and the volume of solution. The first step is to find the amount of moles of CaCl that you have. Using dimensional analysis you can solve.

40g CaClxx(1 mol)/(75.528g CaCl)=.5296 mol

Now we find the molarity by dividing the moles of CaCl by the volume of solution given in the question. Convert the solution into liters, as it's the units you will need to finish the problem.

(.5296 mol CaC)/(.65 l)=.81470M

This is the M_1 in the dilution equation. So plugging in the numbers into the equation it looks like this. 2 L is give to us in the problem and since it's in liters we don't have to convert.

(0.8147)(.65)=(M_2)(2)

Rearranging using some algebra we get

(0.8147)(.65)/(2) = 0.2647mol

Now that we have moles of CaCl we can convert into required mass.

0.2647 mol CaCl x (75.528gCaCl)/(1 mol CaCL = 19.99 g CaCl

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