Prelab Electrochemistry

Chemistry 12 June 1. 2011

Jason Li

The Discussion of

(Dry, Alkaline, Automotive, and Fuel cells)

Objective: The objective of this report is to understand how different cells act and how they work in our life. Also we can develop our knowledge after we have realized the advantages and the disadvantages of each cells, so lets begin our topic!!!!!!!!!!!!! NOW!!!!!!

1. Introduce the different cells, and give a short explanation

2. Give a picture and an example of how is it made of or used

3. Give the Cathode and Anode reaction of each cell

4. Show the advantages and the disadvantages of each cell.

THE DRY CELL

Introduction: The dry cell battery is one of the mostly used common batteries. It was invented in 1885 by a scientist, Sakizou Yai., and been improved in 1887 to become regular battery which we use in living.

At the center of the dry cell battery is a rod called “Cathode”, which is usually made of metal and is surrounded by an electrolyte paste. The cathode and electrolyte paste are wrapped in paper or cardboard. One or more of these cells are sealed into a metal cylinder called an “Anode”, which is commonly made of Zinc or Alkaline.

One of the examples of dry cell battery is “” Zinc-Carbon Battery””

+

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Example: this kind of dry cell battery is commonly used in flashlight, etc. the construction of the battery is shown above.

Chemical reaction of cathode and anode:

Cathode: 2MnO2 (s) + 2NH4+ (aq) + 2e-  2MnO(OH) (s) + 2NH3 (aq)

Or simply: Mn4+ + e-  Mn3+

Anode: Zn(s) + 4 NH3 (aq)  Zn(NH3) 42+ (aq) + 2e-

Or simply: Zn  Zn2+ + 2e-

Overall: Zn(s) + 2MnO2(s) + 2NH4Cl(aq) → Mn2O3(s) + Zn(NH3)2Cl2 (aq) + H2O(l)

Advantage:

1. It is cheap and very easy to make.

Disadvantage:

1. It can not be recharged.

2. It has a relatively short shelf life.

3. It quickly ceases to function if required to produce large currents.

4. The...