a. How many milliliters of a 2% stock solution of potassium permanganate

(KMn04) would be needed to compound the following prescription?

USE THESE STEPS:

Step 1: Write the formula.

V C = V1 C1

Step 2: Substitute values.

(X) (2%) = (120 ml) (.02%)

Step 3: Check units.

(a)

Units of concentration are both percent.

(b) X will have the same units as the volume

on the other side of the equal sign. In this case

"milliliters."

Step 4: Solve for X.

2 X = 2.4

X = 1.2 ml (answer)

solution of potassium permanganate, place it in a graduate, and "q.s." to 120

ml with distilled water.

b. How many grams of 14% zinc oxide ointment can be made from one pound

of 20% zinc oxide ointment?

USE THESE STEPS:

Step 1:

W C = W1 C1

Step 2 & 3: (X) (14%) = (454 g) (20%)

Step 4:

14 X = 9080 X = 648.57142 grams (answer) (can be rounded to

648.57 grams)

MD0802

2-24

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