| time
requ.: |
15 minutes. |
|
objective: |
Model of a car
battery. |
| material: |
- beaker 150ml
- battery 4.5 volts or DC power supply
- crocodile clamps
|
- multimeter
- electrode support
- connection cables
- electric motor U<2V
|
| chemicals: |
 |
 |
|
procedure 1: |
Fill the beaker three quarters of sulfuric acid. Place two
stripes of lead into solution without touching each other. Connect
them to the battery and electrolyze solution for some minutes. |
|
observation 1: |
One strip
turns brown. |
|
interpretation 1: |
Through
oxidation there is obtained brown plumbum(IV)-oxide on one electrode,
through reduction on the other electrode plumbum metal (disproportioning). |
|
procedure 2: |
Take the
battery away and measure the voltage. |
|
observation 2: |
U ~ 2V |
|
interpretation 2: |
Through
oxidation and reduction the lead electrodes were polarized to obtain a
plumbum secondary cell. 6 of such cell serially connected together will
form a car accumulator (U=12V). |
|
procedure 3: |
Connect with
the electromotor. |
|
observation 3: |
The motor runs. |
|
disposal of: |
Fill sulfuric
acid into a flask and reuse for same experiment. |
|
source: |
from Barke, H.-D. et al.: One Hundred
Chemistry-Experiments to Avoid Chalk and Talk; University of Muenster,
2004. |
