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I have this for homework, and I am confused as to how to solve it.
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1. Calculate the mass in 30 ml
68,2 g* 30 ml/250 ml = 8,184 g
Convert this to mole
8,184g/170,482 g/mol = 0,048 mol
The ratio is 0,048 mol/ xl = 0,5 mol/1l
x = 0,096 l = 96 ml
30 ml wie have already so we have to add 96 ml -30 ml = 66 ml H2O

Quote from: ann on December 07, 2022, 03:46:20 PM
I have this for homework, and I am confused as to how to solve it.

Here first calculate molarity of the stock solution .
Molarity = moles / volume in L
Convert 68.2 g CuCl₂.2H₂O ---> moles of  CuCl₂.2H₂O ,

Convert 250mL to L and get molarity of  CuCl₂.2H₂O
Now use dilution law
M₁V₁(stock solution) = M₂V₂(diluted solution)
V₂ = M₁V₁(diluted solution) / M₂

Now amount of water needed to add in 30.0 mL of stock solution is V₂ - 30.0 mL