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1) 
What is the effect on pH of adding sodium benzoate to an aqueous solution of benzoic acid?
Why does this change occur?


2) 
Calculate pH:


a) 
0.150 M C_{6}H_{5}COOH (K_{a}= 6.14 x 10^{5})


b) 
0.150 M C_{6}H_{5}COOH with 0.350 M C_{6}H_{5}COONa
note: Since Na^{+} is a spectator ion, it is ommited from the equation and subsequent calculations. 

3) 
A solution is prepared from 0.150 mole of CH_{3}COOH, 0.010 mole of CH_{3}COONa, and enough water to make a total volume of 1.00 liter. Calculate the [H_{3}O^{+}].
K_{a} for CH_{3}COOH = 1.8 X 10^{5}
(Write your answer in scientific notation using the e symbol. ex: 1000 = 1e3)
note: Since Na^{+} is a spectator ion, it is ommited from the equation and subsequent calculations. 

4) 
Determine the pH of a solution containing 0.085 M NH_{3} and 0.247 M NH_{4}Cl.
K_{b} for NH_{3} = 1.8 X 10^{5}


5) 
What must be the ratio of HAc to NaAc to prepare a buffer whose pH = 4.81?
: 1


6) 
How many grams of NaAc must be dissolved in a 0.200 M HAc solution to make a 400. mL buffer solution with a pH of 4.56?
g


7) 
Which of the following acids (and conjugate base salts) would be the most useful in preparing a buffer solution with a pH of 4.58?
Acid A: K_{a} = 1.8 X 10^{5}
Acid B: K_{a} = 1.36 X 10^{3}
Acid C: K_{a} = 1.6 X 10^{10}
The pK_{a} of Acid A is closest to the pH needed. 

8) 
A solution contains 0.300 moles of HAc and 0.200 moles of KAc in a total volume of 500. mL.


a) 
Determine pH of this solution.


b) 
Determine pH after the addition of 0.100 mole of H_{3}O^{+}.


c) 
Determine pH after the addition of 0.100 mole of OH^{}.


d) 
How many mL of 6.00 M NaOH must be added so that the pH will be equal to the pK_{a}?


9) 
17.8 mL of a 0.344 M H_{2}SO_{4} solution is required to completely neutralize 20.0 mL of a KOH solution. Calculate the concentration of the KOH solution.
M


10) 
Calculate the pH after the following volumes of 0.300 M NaOH have been added to 40.00 mL of 0.600 M HCl. [Consider each addition independent of the others].


a) 
0.00 mL


b) 
5.00 mL


c) 
40.00 mL


d) 
80.00 mL


e) 
80.50 mL


f) 
90.00 mL


11) 
If 25.00 mL of Ca(OH)_{2} requires 18.34 mL of 0.100 M HCl to reach the equivalence point, what is the concentration of the Ca(OH)_{2}?
M


12) 
Calculate the pH at the equivalence point for the titration of:


a) 
50 mL of 0.10 M NH_{3} with 0.10 M HCl


b) 
50 mL of 0.010 M HAc with 0.10 M NaOH


13) 
A solution containing 100.0 mL of 0.135 M HAc is being titrated with 0.540 M NaOH. Find pH at:


a) 
the beginning


b) 
halfway to the equivalence point


c) 
at the equivalence point


d) 
5.00 mL past the equivalence point


14) 
A solution containing 2.049 g of a weak acid required 43.88 mL of 0.1207 M NaOH to reach the equivalence point. What is the gMW of the acid?
g/mol

