Arkansas State University  Department of Chemistry and Physics
CHEM2004	Exam 3b

CHEM2004                                                                 Name_________________________

Exam 3b                                                                       Fall 2009

1.         Given the acid category, match the description that bests fits the species formed in water.  (10 points)

_____ Very strongly acidic cations  

_____ Nonacidic cations           

_____ Feebly acidic cations

_____ Moderately acidic cations

_____ Weakly acidic cations

a) Simply hydrated ions, no hydrolysis occurs

b) Mostly hydrated ions with small amounts of hydroxycations

c) Metal hydroxides precipitate out of solution, must add acid to keep metal ion in solution

d) Reacts irreversibly with water to give insoluble metal oxide or hydroxide

e) React with hydroxide ion to give insoluble metal hydroxides in neutral or slightly basic solutions

 2.         Circle the correct answer:               (12 points)

a)  Higher hydration energy:           Ca⁺² or La⁺³               (same size and c)

b)  Higher hydration energy:           Sr⁺² or Pb⁺²                (same size and charge)

c)  Higher hydration energy:           Ba⁺² or Ca⁺²               (same charge and c)

d)  The more basic anion:                IO₄^- or BrO₄^-

e)  The more basic anion:                BrO₂^- or BrO₄^-

f)  The stronger acid:                       HClO₂ or HClO₃

3.         For the ions below, circle the ones will have color.                     (4 points)

Cd ^{+ 2} 

Cr^{+ 6}  

N ^{- 3}

Na⁺

4.         Label each of the following as either a hydrated ion, hydroxycation, insoluble hydroxide, oxoanion, hydroxyanion, insoluble metal oxide, or oxoacid.            (8 points)

 a) Fe(OH₂)₅(OH)⁺²

 b) NbO₂(OH)₂^{2 -}

 c) CrO₄^{2 -}

 d) Fe(OH)₄ ^2-

 e)  Cr₂O ₃

 f)  Ni(OH₂)₆ ^{2 +}

 g)  H₂SO₃  or SO(OH)₂

 h)  Ti(OH)₄

5.         Determine the oxoanion for each of the following ions.      (10 points)

a)   P ^{+ 5}  

b)  Se ^{+ 4}

c)  V ^{+ 3}

d)  I ^{+ 3}

e)  C ^{+ 4}

6.         Write the net ionic equation for FeCO_{3 (s)}:          (4 points)

7.         The sign for DG for a precipitation reaction.         (2 points)