______  pts. out of 58 possible pts. =              % =                                           Name:

Advanced Chemistry:  Quiz #6 (Redox & Electrochemistry)

 

1.       Balance each of the following redox equations (8 pts. each):

 

                 a.  Cr2O7-2(aq)  +  Cl-(aq)              Cr+3(aq)   + ClO-(aq)     (acidic solution)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                 b.  MnO4-(aq)  + As4O6(aq)              Mn+2(aq)   + H3AsO4(aq)      (acidic solution)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                 c.  MnO4-(aq)   + H2S(g)            MnO2(s)  + S(s)     (basic solution)

 

 

 

 

 

 

 

 

 

 

 

 

 

2.       What is the oxidizing agent in the reaction in problem 1c?  (2 pts.)

 

3.       What is the reducing agent in the reaction in problem 1c?  (2 pts.)

 

4a.     In the space at the bottom of this page, draw the diagram for a battery that uses aluminum, zinc, aluminum nitrate, and zinc nitrate.  Label the cathode, the anode, and the direction of electron flow.  (8 pts.)

 

b.       What is the reduction half reaction in the battery?  (3 pts.)

 

 

 

c.       What is the oxidation half reaction in the battery?  (3 pts.)

 

 

 

d.       What is the balanced net reaction that occurs in the battery?  (3 pts.)

 

 

 

 

 

 

 

 

 

e.       What is the voltage that the battery generates?  (5 pts.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.       If the battery in problem 4 initially has 10.0 g of aluminum and 10.0 g of zinc, how long will the battery last if it generates 250.0 mA of electricity?  (8 pts.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

96,485 Coulombs = 1.0000 mole of electrons