C1V1 = C2V2
Initial inspection of the problem reveals that the concentration units are
different. Either concentration may be converted, the requirement is that both units
must be the same.
Express 0.100 Eq/L Ca(OH)2 in terms of mol/L
0.100 Eq
mol
---------- X ------ = 0.0500 mol/L
L
2 Eq
Using the appropriate expression substitute the values.
C1V1 = C2V2
(6.00 mol/L)(10.0 mL) = (0.0500 mol/L)V2
Solve for the unknown quantity.
6.00 mol/L) (10.0 mL)
V2 = -------------------- = 1200 mL
0.0500 mol/L
6-5.
PREPARATION OF STANDARDS BY MIXING
When preparing a new standard by mixing two or more standards of known
concentration, the concentration of the new standard times its volume is equal to the
sum of the concentration of the first standard times its volume plus the concentration of
the second standard times its volume and so on depending on the number of standards
being mixed. Keep in mind that the concentration of the new standard will never be
greater than the highest standard nor less than the lowest standard. All concentrations
and volumes must be in the same units respectively. An expression that describes the
relationship between the standards being mixed is as follows:
C1V1 = C2V2 + C3V3 . . . + CnVn
Where:
C1 = Concentration of the new standard
V1 = Volume of the new standard (total volume)
C2, C3, Cn = Concentration of the standards used in preparation
V2, V3, Vn = Volume of the standards used in preparation
MD0837
6-8
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