To what volume should you dilute 131 mL of an 8.20 M CuCl2 solution so that 49.0 mL of the diluted solution contains 4.53g CuCl2 ?
Molar mass of CuCl2 is 134.5 g mol^-1
so solution needs to contain
4.53 g / 134.5 g mol^-1
=0.03368 mole
concentration is
0.049 L/0.03368 mole
=1.455 molar
thus we need to dilute the 8.20 M solution by a factor
8.20 M/1.455 M= 5.636
so the new total volume is
131 ml x 5.636
=738.4 ml
check on the concentration
old solution contains
131 x 8.20 mmoles = 1074 mmoles
new solution contains
1.455 x 738.4 mmole = 1074 mmole
Thank you for all the detail, but i'm still confused......so 738.4mL is the answer?
Thank you :)
this answer is incorrect. The following should be switched:
0.049 L/0.03368 mole
=1.455 molar
should be
0.03368 mol/0.049 L
=0.6873 molar
the rest of the steps are correct but you would need to substitute the above number in for the remainder of the problem
To determine the volume to which you should dilute the solution, you need to use the concept of molarity (M) and the equation for dilution:
M1V1 = M2V2
Where:
M1 = initial molarity of the solution = 8.20 M
V1 = initial volume of the solution = 131 mL
M2 = final molarity of the solution (after dilution)
V2 = final volume of the solution (after dilution) = ?
First, let's calculate the moles of CuCl2 in 49.0 mL of the diluted solution using the given mass:
molar mass of CuCl2 = atomic mass of Cu + (2 x atomic mass of Cl)
= 63.55 g/mol + (2 x 35.45 g/mol)
= 63.55 g/mol + 70.90 g/mol
= 134.45 g/mol
moles of CuCl2 = mass / molar mass
= 4.53 g / 134.45 g/mol
≈ 0.0337 mol
Now, we can use the equation for dilution, M1V1 = M2V2, to solve for V2:
M1 = 8.20 M (given)
V1 = 131 mL (given)
M2 = ? (unknown)
V2 = ? (unknown)
Substituting the given values into the equation:
8.20 M x 131 mL = M2 x V2
Now, we can solve for V2 by rearranging the equation:
V2 = (8.20 M x 131 mL) / M2
To find M2, we can use the moles of CuCl2 calculated earlier and the volume V2 = 49.0 mL:
M2 = moles of CuCl2 / V2
Substituting the values:
M2 = 0.0337 mol / 49.0 mL
Finally, substitute M2 back into the equation for V2:
V2 = (8.20 M x 131 mL) / (0.0337 mol / 49.0 mL)
Simplify the equation by performing the division and multiplication:
V2 ≈ 16899 mL
Therefore, you need to dilute 131 mL of an 8.20 M CuCl2 solution to a volume of approximately 16899 mL (or 16.9 L) in order to obtain a solution where 49.0 mL contains 4.53 g of CuCl2.