Question

To what volume should you dilute 133 mL of an 7.95 M CuCl2 solution so that 49.0 mL of the diluted solution contains 4.27 g CuCl2? Express your answer in milliliters.

Answer 1

calculate the molarity of final solution

Molar mass of CuCl2,

MM = 1*MM(Cu) + 2*MM(Cl)

= 1*63.55 + 2*35.45

= 134.45 g/mol

mass(CuCl2)= 4.27 g

number of mol of CuCl2,

n = mass of CuCl2/molar mass of CuCl2

=(4.27 g)/(134.45 g/mol)

= 3.176*10^-2 mol

volume , V = 49.0 mL

= 4.9*10^-2 L

Molarity,

M = number of mol / volume in L

= 3.176*10^-2/4.9*10^-2

= 0.6481 M

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use dilution formula

M1*V1 = M2*V2

1---> is for stock solution

2---> is for diluted solution

Given

M1 = 7.95 M

M2 = 0.6481 M

V1 = 133.0 mL

Use:

M1*V1 = M2*V2

V2 = (M1 * V1) / M2

V2 = (7.95*133)/0.6481

V2 = 1631 mL

Answer: 1.63*10^2 mL