Calculating Cell Potentials

Electrochemical Cell Potential

The tendency of a substance to gain electrons is called its

REDUCTION POTENTIAL

Why do we care about cell potential?

• Because the difference in potential is what gives us VOLTAGE (power)!!!!!!!!

What is this difference is potential we are talking about?

• When a reduction reaction is coupled with an oxidation reaction, the difference between the half reactions is what gives us our voltage!

Calculating potentials: (E°Cell)

Use this formula:

E°reduction - E°oxidation

Opener

The following picture of an electrochemical cell has lead and zinc electrodes:

Color the zinc electrode green and the lead electrode red. (You decide which is which)...

Label the anode with a yellow sign and cathode with a black sign (plus or minus sign).

Indicate the direction of electron flow in the wire with a brown colored pencil.

Color the salt bridge yellow.

Color the solution in the oxidation half cell pink and the solution in the reduction half cell orange.

Standard hydrogen electrode:

• Voltage equals ZERO

Quiz

1. The tendency of a substance to gain electrons is its:

a. reduction potential b. oxidation potential

c. hydrogen potential d. half-cell difference

2. The potential of a standard hydrogen electrode is how many volts?

a. 1.5 b. 0

c. 2.4 d. 10

3. The half reactions in the table were all written as:

a. oxidations b. potentials

c. reductions d. differences