Chemistry 1410 – Spring 2005                                                 Practice Problems for Chapters 15 – 16

 


Chapter 15

 

1)  Calculate the pH of the following solutions:

a)      2.8 x 10-4 M Ba(OH)2 pH = 10.75

b)      5.2 x 10-4 M HNO3 pH = 3.28

 

2)      Calculate the [ H3O+ ] in the following solutions:

a)      A solution whose pH =5.20 6.31 x 10-6

b)      A solution with [OH-] = 3.7 x 10-9 M 2.7 x 10-6

 

3) Calculate the pH  of a 0.350 M solution of benzoic acid (C6H5COOH).  Ka = 6.5 x 10-5 pH = 2.82

 

4) Calculate the pH of a 0.450 M solution of the weak base pyridine (C6H5N).  Kb = 1.7 x 10-9 pH = 9.5

 

5) Calculate the pH of the following solutions:

            a) 0.36 M CH3COONa  pH = 9.15

            b) 0.42 M NH4Cl  pH = 4.82

 

Chapter 16

 

6)         a) Calculate the pH of a formic acid/formate buffer where [HCOOH] = 0.250 M and the [HCOONa] = 0.450 M.

                        pH = 4.02

           b) Calculate the change in pH when 0.120 mol H+ is added to 500.0 mL of this buffer (assume no volume change).

                        pH = 3.4

            c) Calculate the change in pH when 0.080 mol OH- is added to 500.0 mL of the buffer (assume no volume change).

                        pH = 4.6

7) A solution of 50.0 mL of 0.200 M HNO3 is titrated with 0.100 M NaOH. 

 

            a) Calculate how many milliliters of 0.100 M NaOH will be required to reach the equivalence point.

                        100 mL

            b) What would be the pH at the equivalence point?

                        pH = 7

            c) What would be the pH when an additional 5.00 mL of 0.100 M NaOH is added beyond the equivalence point?

                        pH = 11.5

8) In a titration experiment, 12.5 mL of 0.500 M H2SO4 neutralize 50.0 mL of NaOH.  What is the concentration of the NaOH solution?           0.25 M