Solve Dilution: 125 mL 8.00M CuCl2 to 50 mL 5.9 g CuCl2

[FuturePA]

Homework Statement

To what volume shuould you dilute 125 mL of an 8.00 mL CuCl2 solution so that 50.0 mL of the diluted solution contains 5.9 g CuCl2?

Homework Equations

M= mol solute / vol solution (L)
m = mol solute / mass solvent (kg)
mole percent = mol solute / mol solute + solvent

The Attempt at a Solution

8.00 M = mol CuCl2 / .125 L
1 mol CuCl2 x (65.55 + 2(35.45)g / 1 mol CuCl2 = 134.45 g CuCl2
5.9 g CuCl2 (final) x (1 mol CuCl2) / (65.55 +2(35.45)g = .4388 mol CuCl2
8.00 M = .44 mol CuCl2 --> .055 L solution??
I don't know how to use these formulas to find the diluted amount using the old amount? Do I subtract the grams CuCl2 to the new Molarity and find the tot vol? The answer is not the same as the back of the book.
THANKS SO MUCH!

 

[Borek]

How many moles of CuCl₂ do you have?

What molarity do you need?

C=n/V

 

[FuturePA]

Vapor Pressure Problem

An aq CaCl2 colution has a vapor pressure of 81.6 mmHg at 50 degrees C. The vapor pressure of pure water at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent?

I don't even know where to start, if I can use Raoult's Law or not . . .

 

[Borek]

You can. Just assume that whatever is dissolved has a vapor pressure of zero.

 

[EternityMech]

The question doesn't even make any sense.

you have 0.125dm3 of 8 molar CuCl2 and you want to turn it into 0.050dm3 of CuCl2?

 

[EternityMech]

is the answer 9.09m3?

im guessing its a typo and you have 8 molar CuCl2 you need to dilute it so that 0.050dm3 has 0.044moles.

divide 8 moles with 0.044 and you get 181.81 then divide that with 0.050.