1. Energy in a cell
Today, we will learn to figure out how much energy we can get out of a cell
You will need:
Periodic Table
CALCULATORS!

2. 1 M ion solution (concentration) 25 ºC (temperature) 1 atm (pressure)
Electrochemistry: Basic Concepts
Standard conditions:
1 M ion solution (concentration)
25 ºC (temperature)
1 atm (pressure)

3. Copper-Hydrogen cell under standard conditions
Electrochemistry: Basic Concepts
Copper-Hydrogen cell under standard conditions
H2 (g) + Cu2+(aq) → 2H+(aq) + Cu(s)
(net ionic equation)
Cell notation
H2 | H+ || Cu2+ | Cu
reduction half-cell
CATHODE
oxidation half-cell
ANODE
salt bridge and wire

4. Eºcell = Eºreduction - Eºoxidation
Cell Potential
Standard Reduction Potentials (Eº): shows how likely a ½ reaction is to reduce (gain electrons)
To find a voltaic cell’s standard potential (how many volts it can use):
Eºcell = Eºreduction - Eºoxidation
HINT: Write down everything. Show all work. When you do it in your head, you get confused.

5. Examples: Find the cell potential of a copper-zinc cell.
Electrochemistry: Basic Concepts
Examples: Find the cell potential of a copper-zinc cell.
Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(aq)
Step 1: Cell notation:
Zn | Zn2+ || Cu2+ | Cu
Step 2: ID ox and red ox
red
Step 3: Find reduction potentials
Zn2+|Zn V
Cu2+ | Cu V
Step 4: Equation
Eºcell = Eºred - Eºox

6. Examples: Find the cell potential of a copper-zinc cell.
Electrochemistry: Basic Concepts
Examples: Find the cell potential of a copper-zinc cell.
Step 4: Equation
Eºcell = Eºred - Eºox
= EºCu2+|Cu - EºZn2+|Zn
= V – ( V)
= V
The standard reduction potential of the copper-zinc cell is V

7. Try it out! Calculate the cell potential:
Additional Assessment Questions
Try it out!
Calculate the cell potential:
2Ag+(aq) + Co(s) → Co2+(aq) + 2Ag(s)
+ 1.08V

8. In a Electrochemical cell… when Eº = (+), it is spontaneous
Electrochemistry: Basic Concepts
A spontaneous reaction: proceeds naturally. Voltaic cells are always spontaneous.
A non-spontaneous reaction: requires an outside influence to proceed. (eg. forcing the electrons in the opposite direction)
In a Electrochemical cell…
when Eº = (+), it is spontaneous
when Eº = (-), it is not spontaneous

9. Are these spontaneous or not?
Electrochemistry: Basic Concepts
Are these spontaneous or not?
Eºcell = V
Eºcell = V
Eºcell = V
Eºcell = V
Eºcell = V
spontaneous
not spontaneous

10. Try it out!
Calculate the cell potential to determine if each of these redox reactions is spontaneous.
Mn2+ + 2Br- → Br2 + Mn
Fe2+ + Sn2+ → Fe3+ + Sn
Ni2+ + Mg → Mg2+ + Ni
Pb2+ + Cu+ → Pb + Cu2+
V, nonspontaneous
V, nonspontaneous
V, spontaneous
V, nonspontaneous