CHM 1033 Class Assignment #6                                    Name __________________________

 

Module 6

 

1.  For each of the following properties, indicate whether it is characteristic of acids, characteristic of bases, or characteristic or both acids and bases.

 

a.  bitter taste    __base _______       b.  water solutions conduct electricity          _acids and bases

 

c.  slippery        __base _______       d.  turns blue litmus paper red                     __acid______

 

e.  sour taste     __acid______           f.  produce H+ ions when dissolved in H2O  __acid______

 

g.  produce OH- ions when dissolved in H2O     __base _______

 

2.  Classify each of the following as a strong acid, a weak acid, a strong base, or a weak base.

 

a.  HC2H3O2   __ weak acid __     b.  Zn(OH)2  _weak base    _   c.  HNO3  ___strong acid   _

 

d.  RbOH   _strong base        e.  HCl   _strong acid         f.  HF   _weak acid        g. NH4OH  _weak base         

 

3.  Complete the following table.

                

    pH

   pOH      

  [H+]       

   [OH-]

acidic, basic, or neutral

      5

      9

1 x 10-5

1 x 10-9

    acidic

      4

     10

1 x 10-4

1 x 10-10

    acidic

      2

     12

1 x 10-2

1 x 10-12

    acidic

      7

      7

1 x 10-7

1 x 10-7

    neutral

     11

      3

1 x 10-11

1 x 10-3

    basic

     12

      2

1 x 10-12

1 x 10-2

    basic

      9

      5

1 x 10-9

1 x 10-5

    basic

 

4.  Complete and balance the following acid-base neutralization reactions.

 

a.     H3PO4   +   3 NaOH  ®     Na3PO4   +     3 HOH 

 

b.     Al(OH)3    +    3 HCl   ®    AlCl3    +    3 HOH   

 

c.     Ba(OH)2    +    2 HNO3    ®    Ba(NO3)   +   2 HOH

 

d.     3 H2SO4     +     2 Mn(OH)3    ®   Mn2(SO4)3  +   6 HOH

 

e.      H2SO4     +     2 NH4OH     ®    (NH4)2SO4     +   2 HOH

 

5.  Which of the following pairs of compounds, when dissolved in water, make a buffer solution.   Circle the correct choice(s).

 

a.  HCl and NaCl                 b.  H3PO4 and NaH2PO4           c.  HNO2 and NaNO2

 

d.  NH3 and NH4Cl              e.  NaOH and Na2SO4               f.  HNO3 and NaNO3

 

6.  Which of the following occurs when HCl is mixed with an excess of buffer solution.  Circle the correct choice.

 

  a.  the pH increases slightly      b.  the pH decreases slightly    c.  the pH stays exactly the same  

 

  d.  the pH increases significantly             e.  the pH decreases significantly

 

7.  Which of the following occurs when NaOH is mixed with an excess of buffer solution.  Circle the correct choice.

 

  a.  the pH increases slightly      b.  the pH decreases slightly    c.  the pH stays exactly the same  

 

  d.  the pH increases significantly             e.  the pH decreases significantly

 

8.  Which of the following occurs when HCl is mixed with a solution that is not a buffer solution.  Circle the correct choice.

 

  a.  the pH increases slightly      b.  the pH decreases slightly    c.  the pH stays exactly the same  

 

  d.  the pH increases significantly             e.  the pH decreases significantly

 

9.  Which of the following occurs when NaOH is mixed with a solution that is not a buffer solution.  Circle the correct choice.

 

  a.  the pH increases slightly      b.  the pH decreases slightly    c.  the pH stays exactly the same  

 

  d.  the pH increases significantly             e.  the pH decreases significantly

 

10. Write the equation for the reaction which occurs when HCl is added to a buffer solution containing HF and NaF.

 

          HCl   +    NaF    ®    NaCl   +   HF

 

11.     Write the equation for the reaction which occurs when NaOH is added to a buffer solution containing HC2H3O2 and NaC2H3O2.

 

          NaOH   +    HC2H3O2    ®    Na C2H3O2   +   HOH