4.15.2012

Dilution

DILUTION SOLUTIONS

  • when two solutions are mixed, the concentration changes
  • dilution is the process of decreasing the concentration by adding a solvent (usually water)
  • the amount of solute does not change
  • because concentration is mol/L, we can write:
C = n/V                C1V1 = C2V2
n = CV

ex. determine the concentration when 100 ml of 0.10 M HCl is diluted to a final volume of 400 mL.
V1 = 100mL
C1 = 0.10 M
V2 = 400 mL
C2 = ?

C1V1 = C2V2
(0.1)(100) = C2(400)
C2 = 0.025 M

ex. how much water must be added to 10.0 mL of 10.0 M Na2SO4 to give a solution with a concentration of 0.50 M?
V1 = 10.0 mL
C1 = 0.1 M
V2 = ?
C2 = 0.50 M

C1V1 = C2V2                                  ΔV = 200 - 10 = +190 mL
(10.0)(10.0) = (0.5)V2
V2 = 200 mL

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