a. **Example 1**. You are preparing a series of standards for an automated

glucose procedure. You already have a 50.0 mg/dL and a 300 mg/dL standard made,

and are making intermediate concentrations by mixing various quantities of the two. If

you mix 3.00 mL of the 50.0 mg/dL standard with 2.00 mL of the 300 mg/dL standard,

what is the concentration of the new standard?

Solution. Read the problem carefully and select the formula that will allow

you to solve the problem for the unknown quantity.

C1V1 = C2V2 + C3V3 . . . + CnVn

Ensure that all concentrations and volumes are expressed in the same units,

respectively. (This problem does not require any concentration or volume unit

conversion.)

To determine V1, add the volumes of each of the standards being mixed. In

this problem, V1 equals 5.00 mL since 3.00 mL of the 50.0 mg/dL standard and 2.00 mL

of the 300 mg/dL standard are being mixed.

Substitute the given information and solve for the unknown quantity.

C1 (5.00 mL) = (50.0 mg/dL)(3.00 mL) + (300 mg/dL)(2.00 mL)

(50.0 mg/dL)(3.00 mL) + (300 mg/dL)(2.00 mL)

C1 = ------------------------------------------

5.00 mL

C1 = 150 mg/dL

b. **Example 2**. What is the concentration of a standard solution that was

prepared by mixing 5.0 mL of a 6.0 Eq/L Ca3(PO4)2 standard, 8.0 mL of a 2.0 mol/L

Ca3(PO4)2 standard, and 3.0 mL of a 31 g/dL Ca3(PO4)2 standard?

Solution. Read the problem carefully and determine the relationship that will

allow you to solve the problem for the unknown quantity.

C1V1 = C2V2 + C3V3 . . . + CnVn

Ensure that all concentrations and volumes are expressed in the same units,

respectively.

In this example, convert the concentrations to mol/L. Consistency of the units

is the only requirement. One unit is not preferred over another in this type of

calculation.

MD0837

6-9

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