Step 2: Determine the number of milliliters of concentrated HNO 3 solution that is needed.

.

.

' .'

1

25 10

200

mole H (^100013)
mole H
mL sol n mL sol n
#^3

=

-+

11. Calculate the mass of 1 equivalent of Sr(OH) 2. Assume complete ionization:

Sr OH^ h (^2) ]aqg"Sr]]^2 aq+gg+ 2 OH-aq
A. 15.21 g
B. 30.41 g
C. 60.82 g
D. 121.64 g
E. 243.28 g
Answer: C
The gram-equivalent weight (GEW) of a base is the mass of the base (in grams) that will
provide 1 mole of hydroxide ions in a reaction or that will react with 1 mole of H+ions. This
problem can be done by using the factor-label method.
..)
1
121 64
2
1
1
60 82
mole Sr(OH)
g Sr(OH)
equiv. Sr(OH)
mole Sr(OH)
equiv. Sr(OH)
2 g Sr(OH
2 2
2
2
#^2 =
Note: Had the reaction been
Sr OH^ h (^2) ]aqg++H]+aqg"Sr OH^ h]+aqg H O (^2) ]lg
there would have been only 1 equivalent per mole. In other words, you must know the specific
reaction in order to use the concept of equivalents.
Part II: Specific Topics