preparation of standard solution by dilution. dilution: decreasing the concentration of a solution...
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Preparation of Standard Solution by dilution
Preparation of Standard Solution by dilution
Dilution: Decreasing the concentration of a solution by adding more solvent
Stock Solution: The solution you start with (A higher concentration)
Example 1The concentration of the stock solution is 5M. If
we use 10mL of this solution to make a 250 mL solution what will the new concentration be?
Vi =
Ci =
Vf =
Cf =
Example 1The concentration of the stock solution is 5M. If
we use 10mL of this solution to make a 250 mL solution what will the new concentration be?
(Stock solution)Vi = 10mL
Ci = 5M
(Solution we are making)Vf =
Cf =
Example 1The concentration of the stock solution is 5M. If
we use 10mL of this solution to make a 250 mL solution what will the new concentration be?
(Stock solution)Vi = 10mL
Ci = 5M
(Solution we are making)Vf = 250mL
Cf = X (unknown)
Calculations
CiVi = CfVf
(5M)(10mL) = (X)(250mL)
Rearrange so it looks more familiar
50 = 250XDivide both sides by 250 (solve for X)
50 = X 250
X = 0.2M
Example 2The concentration of the stock solution is unknown.
We use 100mL of this solution to make a 500 mL solution. If this new solution was tested to be 0.1M what was the concentration of the stock solution?
Vi =
Ci =
Vf =
Cf =
Example 2The concentration of the stock solution is unknown.
We use 100mL of this solution to make a 500 mL solution. If this new solution was tested to be 0.1M what was the concentration of the stock solution?
Vi = 100mL
Ci = X
Vf = 500mL
Cf = 0.1M
Calculations
CiVi = CfVf
(X)(100mL) = (0.1M)(500mL)
Rearrange so it looks more familiar
100X = 50Divide both sides by 100 (solve for X)
X = 50 100
X = 0.5M
Assignment
See note handout