c. How many milliliters of 10% povidone-iodine (Betadine ) solution would be

needed to make 4 liters of a 1:2000 Betadine solution?

USE THESE STEPS:

Step 1: V C = V1 C1

Step 2: (X) (10%) = (4 L) ( 1 )

2000

Step 3: (a) Change 4 liters to milliliters

(b)

Change 10% to a ratio by placing the 10 over 100.

(X) (10) = (4000 ml) ( 1 )

100

2000

equal sign are multiplied by the same number, the sides will still be equal. The

easiest way to simplify an equation having ratios on both sides of the equal

sign is to multiply both sides of the equal sign by the larger denominator. In

this case the larger denominator is 2000; therefore, multiply both sides by

2000.

(X) (20,000) = (4000 ml) (2000)

100

2000

*200 X = 4000 ml

X = 20 ml

*When zeros trail whole numbers on both sides of the equal sign, an equal number of

zeros may be cancelled on each side without changing the value of the equation.

d. How many milliliters of a 1:200 silver nitrate solution would be needed to

make 2000 ml of a 1:4000 solution?

V C = V1 C1

(X)

(1)

= (2000 ml) ( 1 )

200

4000

(X) (4000) = (2000 ml) (4000)

200

4000

20 X = 2000 ml

X = 100 ml

MD0802

2-25

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