REDOX REACTION JANE Flashcards
What does a redox reaction involve?
A redox reaction involves the transfer of (an) electron(s) from one substance to another
Define oxidation
Oxidation is the loss of electrons (OIL)
Define Reduction
Reduction is the gain of electrons (RIG)
The substance being oxidised is the:
REDUCING AGENT
The substance being Reduced is the:
OXIDISING AGENT
What are oxidising numbers used for
To work out whether oxidation or reduction is happening to something
Rules of oxidation
1) O.N of hydrogen is +1 in a compound (except for hydrides)
2) O.N of oxygen is -2 in a compound (except F2O, H2O2)
3) O.N of a free element is 0
4) In a compound, monatomic atoms take ion charge
5) All O.N add up to the overall charge of the molecule
Steps for balancing half equations (KOHES)
1) Balance Key element
2) Balance O with h2o
3) Balance H with H+
4) Balance Electrons with e-
5) Add STATES
What is the electrochemical series
A list of reactions listed as reductions.
What does the strongest oxidising agent react with
The strongest oxidising agent always reacts with the strongest reducing agent.
Strongest oxidising agent is top left, strongest reducing agent is bottom right
FORMS S SHAPE
What is the Salt Bridge
Usually.a filter paper soaked with KNO3.
Roles of the Salt bridge
1) Maintain electrical neutrality
2) Complete the circuit
Why is KNO3 often used in the salt bridge
Has a high solubility in water and does not react with the chemical present
Which electrode does oxidation occur in
The anode, has negative charge
Which electrode does reduction occur in
The cathode, has positive charge
Mnemonic for Anode, Cathode, redox
AN OIL RIG CAT
What 2 components does a Galvanic cell have
An internal circuit
An external circuit
What is the internal circuit of a galvanic cell
Electrolytes(ion solutions) +Salt bridge through which ions move and carry the current, thus completing the circuit
What Is the external circuit of a galvanic cell
The wire through which electrons (e-) move
Formula for EMF Voltage within a cell
Voltage = E^o (oxidating agent) – E^o (reducing agent)
=ALWAYS POSITIVE as it is voltage supplied when the spontaneous reaction occurs
Standard Conditions
1M Concentration, 1ATM, 298*k)
Why don’t you observe the 2 products you predict from the electrochemical series
1) Rate of reaction too slow
2) Not standard conditions were used (Not 25*C, 1ATM, 1M Solution)
How to predict whether a reaction with proceed from E^0 Values
the oxidising agent must be on top of the reducing agent
