______� 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