ELECTROCHEMISTRY
Physical Science
Grade 12
Kimberly Fourie
[Type here]
, 1
ELECTROCHEMISTRY
Oxidation: loss of electrons/increase in oxidation number.
Reducing agent: a substance that is oxidised/loses electrons.
Reduction: gain of electrons/decrease in oxidation number.
Oxidising agent: a substance that is reduced /gains electrons.
Anode: the electrode where oxidation takes place.
Cathode: the electrode where reduction takes place.
Electrolyte: a solution that conducts electricity through the movement of ions.
Standard reduction potentials:
• Use table 4B – must start with Li.
• Uses of the table:
o Determines spontaneity.
o Identify oxidising and reducing agents.
o Calculate EMF (the further away two half-cell reactions, the higher the EMF).
o Balance redox reactions.
• Oxidising agents on the left and reducing agents on the right.
• Left to right is reduction and right to left is oxidation.
GALVANIC/VOLTAIC CELLS
Spontaneous:
• When two reactants are joined on table, a positive gradient forms.
• Talk about relative strengths when explaining.
• Positive EMF value.
Energy conversion: chemical energy → electrical energy
Electrodes: anode is negative, and cathode is positive.
Uses of galvanic cells: torch cells, car batteries etc.
Current flow: anode to cathode.
Salt bridge:
• Completes the internal circuit.
• Maintains electrical neutrality.
• Salts must be soluble (mustn’t precipitate) therefore choose nitrate when uncertain.
• Cations (+) move towards cathode and anions (-) move towards anode.
Kimberly Fourie
Physical Science
Grade 12
Kimberly Fourie
[Type here]
, 1
ELECTROCHEMISTRY
Oxidation: loss of electrons/increase in oxidation number.
Reducing agent: a substance that is oxidised/loses electrons.
Reduction: gain of electrons/decrease in oxidation number.
Oxidising agent: a substance that is reduced /gains electrons.
Anode: the electrode where oxidation takes place.
Cathode: the electrode where reduction takes place.
Electrolyte: a solution that conducts electricity through the movement of ions.
Standard reduction potentials:
• Use table 4B – must start with Li.
• Uses of the table:
o Determines spontaneity.
o Identify oxidising and reducing agents.
o Calculate EMF (the further away two half-cell reactions, the higher the EMF).
o Balance redox reactions.
• Oxidising agents on the left and reducing agents on the right.
• Left to right is reduction and right to left is oxidation.
GALVANIC/VOLTAIC CELLS
Spontaneous:
• When two reactants are joined on table, a positive gradient forms.
• Talk about relative strengths when explaining.
• Positive EMF value.
Energy conversion: chemical energy → electrical energy
Electrodes: anode is negative, and cathode is positive.
Uses of galvanic cells: torch cells, car batteries etc.
Current flow: anode to cathode.
Salt bridge:
• Completes the internal circuit.
• Maintains electrical neutrality.
• Salts must be soluble (mustn’t precipitate) therefore choose nitrate when uncertain.
• Cations (+) move towards cathode and anions (-) move towards anode.
Kimberly Fourie
