2. Redox #’s 1-5
#1) The reaction absorbs energy, therefore it is electrolytic (A).
#3) Electrolysis requires an external power source (A).
#4) Reduction occurs at the cathode and the positive ion will migrate towards the negatively charged electrode (A).
#5) AN OX → RED CAT
(D)-oxidation at anode.

3. #6) Electrolysis, negative electrode → cathode → Reduction → Gain of e-’s
NaCl(aq) → Na+ + Cl (D)
Cl0 → Cl- + 1e-
#7) From the reaction
Pb0 + Cu+2 → Pb2+ + Cu0
The lead (Pb) is oxidized (anode) and the copper is reduced (cathode). FATCAT-Flow from anode to cathode. OR Pb(s) to Cu(s)

4. Formation of Aluminum Oxide
#8)
Al0 → Al3+
O20 → O-2
+ 3e- 4
OR 4Al0 → 4Al3+ +12e-
4e- + 3
OR 3O e- → 6O2-
b. The oxidation # in Al2O3 is -2.

5. Zinc Chromium Electrochemical Cell
Increase in oxidation # means Oxidation.
Zn0 + Cr3+ → Zn Cr0
2e- lost 3 2 2
A reduction (dec.) in oxidation # means umm…..
3e- gained
Zn0 → Zn2+
Cr3+ → Cr0
+ 2e- 3
3e- + 2
OR 3Zn0 → 3Zn2+ +6e-
OR 2Cr3+ + 6e- → 2Cr0

6. Problems 9-14 #9) Cr3+ + 3e- → Cr0 #10) The Cr3+ gains electrons
The Zn0 loses electrons
#11) Nothing happens to the PROTONS, redox is the loss/gain of ELECTRONS ONLY!!!
#12) RED CAT – Reduction
#13) Zn0 → Zn2+ + 2e-
#14) Zn Cr3+ → 3Zn Cr0

7. The fork is the cathode because: (A)
#15 ELECTROLYSIS
D.C. SOURCE
(BATTERY)
1e-
1e-
The fork to be electroplated
1e- +
Ag0 Ag
Ag1+ - - - +
Ag1+
1e- - -
THE ANODE IS SOLID SILVER, THE SOURCE OF SILVER IN THIS REACTION.
Ag0 +
The fork is the cathode because: (A)
It is the negative electrode in electroplating
It is the site where the silver ions are reduced to make a layer of solid silver (Ag+1 + 1e- →Ag0)

8. Ions move through salt bridge
#17 & 18
Zinc/Copper Cell
2e-
2e-
VOLTMETER
2e-
2e-
Na+
SO42-
Na+
SO42-
SO42-
Na+ Na+
2e- Zn Cu
2e- -
Zn2+
#17) B
A→F →E →D
#18) D
Ions move through salt bridge
Cu2+ Cu
Na+ Na+
SO42- + -
Cu2+ Cu + - -
SO42- +
Zn0(s)  2e- + Zn2+
2e- + Cu2+  Cu0(s)
ANODE (ANOX)
CATHODE (REDCAT)

9. (D) electrolytic cells use an applied energy source.
Electrons flow from anode to cathode, identify which metal is oxidized using Table J.
The function of the salt bridge is to transfer ions and maintain charge.
Zn0 → Zn2+ + 2e-
(A) cathode at B
Cl- ion will be attracted to the positive electrode and oxidized there.
Zn Ag+ → Zn Ag0
(D) The concentration of Zn+2 increases.