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