ap chemistry electroplating

1. electrochemistry
Volts Amps and Coulombs!

2. Luigi Galvani
• Discovered that frog’s leg moved when touched by
something with “static” electricity.
• Animals systems of muscles are controlled and
activated by electricity
• 1780
• A galvanic cell is a
different name for a battery.
FRANKENSTEIN written after
Author Mary Shelley heard about
Galvani’s work.

3. Allessandro Volta
• Found that two different metals together can
“exchange electrons” where one gains and the
other loses them. REDOX.
• Touch a frog’s leg with two different metallic
probes and the leg “jumps”
• OIL RIG
• LEO GER
• Has the “volt” named after him

4. Voltaic Pile
Zinc “LOSES” electrons OIL
Copper+2 gains electrons RIG
This “flow” of electrons between the
two is called electricity

5. Voltaic Pile
Zinc “LOSES” electrons OIL
Copper+2 gains electrons RIG
This “flow” of electrons between the
two is called electricity
Electrons come
out of the
battery here

6. Daniel Cell
• A variation of Volta’s “pile” that was easier to
use and more portable.
• Still used Zn and Cu as metals of choice.
• Later changed to make even easier to use in a
variation called the “crowfoot” or “gravity”
cell.
• Used in telegraph operations to generate
electrical current until 1950’s.

7. Gravity/Crowfoot cell
As Zinc metal changes into zinc ions they
dissolve in the solution, this electrode
disappears. When gone = battery dead!
Cu+2 ions come out of solution, making Cu
electrode larger!

8. Gravity/Crowfoot cell
At a glance, telegraph operators could
look and see how much “battery life”
was left, just like you looking at your %
on your cell phone. Zn crowfoot getting
smaller?? Better get another one ready
to put in!!

9. Gravity/Crowfoot cell
Why called a GRAVITY CELL?
Copper sulfate solution is more dense
and gravity keeps it at the bottom of the
beaker.

10. Gravity/Crowfoot cell
AT night you “recharge” your cell phone.
Basically you’re making the reaction run
IN REVERSE!!

11. Gravity/Crowfoot cell
Calculate the voltage of the Daniel Cell
using Zn/Cu+2
GET OUT AP PACKET!!