the percent assay (%A) times an appropriate conversion factor to yield the desired unit

of concentration. Concentrated commercial liquids are based on g/mL of solution.

a. **Conversion from g/mL to g/dL**. Percent concentration is based on grams of

solute per 100 mL of solution.

Example. What is the g/dL concentration of a HNO3 solution that has a

specific gravity of 1.42 and an assay of 70.0 percent

Solution. Express the desired unit of concentration (g/dL) using the

information given as appropriate factors.

Calculate the grams of HNO3 per milliter of concentrated liquid.

1.42 g 70.0

------X ------= 0.994 g HNO3/ mL concentrated liquid

mL

100

Calculate the g/dL concentration by multiplying the grams of solute per

milliliter of concentrated liquid times an appropriate unit volume conversion factor.

0.994 g

100 mL

--------X ----------= 99.4 g/dL

mL

1 dL

b. **Conversion from g/mL to mol/L**. Molarity is based on moles of solute per

liter of solution.

Example. What is the mol/L concentration of a HNO3 solution with a S.G. of

1.42 and an assay of 70.0 percent.

Solution. Express the desired unit of concentration (mol/L) using the

information given as appropriate factors.

Calculate the GMW of the compound.

HNO3

H

1.0 x 1 =

1.0

N

14.0 x 1 = 14.0

O

16.0 x 3 = + 48.0

63.0 g/mol

MD0837

8-7

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