3) How many grams of solid potassium fluoride should be added to 1.50 L of a 8.35×10-2 M hydrofluoric acid solution to p

[answerhappygod]

3) How many grams of
solid potassium fluoride should
be added to 1.50 L of
a 8.35×10-2 M hydrofluoric
acid solution to prepare a buffer with a pH
of 2.473 ?

grams potassium fluoride =
4) a) Design a buffer that has a pH
of 9.77 using one of the weak
acid/conjugate base systems shown below.
How many grams of the sodium salt of the
weak acid must be combined with how many grams of
the sodium salt of its conjugate base,
to produce 1.00 L of a buffer that
is 1.00 M in the weak base?

grams sodium salt of weak acid =

grams sodium salt of conjugate base
=
b) Design a buffer that has a pH
of 10.87 using one of the weak
acid/conjugate base systems shown below.
How many grams of the sodium salt of
the weak acid must be combined with how many grams of
the sodium salt of its conjugate base,
to produce 1.00 L of a buffer that
is 1.00 M in the weak base?

grams sodium salt of weak acid =

grams sodium salt of conjugate base
=
5) a) A buffer solution
contains 0.465 M KH2PO4 and 0.249 M K2HPO4.
Determine the
pH change when 0.110 mol NaOH is
added to 1.00 L of the buffer.

pH after addition − pH before addition =
pH change =
b) A buffer solution
contains 0.477 M NaH2PO4 and 0.314 M K2HPO4.
Determine the
pH change when 0.091 mol HBr is
added to 1.00 L of the buffer.

pH change =
6) a) What is the pH at the equivalence point in the titration
of a 21.5 mL sample of
a 0.334 M
aqueous hydrocyanic acid solution with
a 0.374 M aqueous potassium
hydroxide solution?

pH =
b) A 31.3 mL sample of
a 0.449 M
aqueous hypochlorous acid solution is
titrated with a 0.399 M
aqueous barium hydroxide solution. What
is the pH after 6.83 mL of base have
been added?

pH =
7) a) A 21.6 mL sample
of 0.330 M diethylamine, (C2H5)2NH,
is titrated
with 0.261 M perchloric
acid.

After adding 12.2 mL
of perchloric acid, the pH is .

Use the Tables link in the References
for any equilibrium constants that are required.
b) A 28.7 mL sample
of 0.257 M ammonia, NH3,
is titrated
with 0.262 M nitric
acid.

After adding 43.4 mL
of nitric acid, the pH is .

Use the Tables link in the References
for any equilibrium constants that are required.