Physical Chemistry- Electrode Potentials Flashcards
Define oxidation in terms of electrons
Oxidation is the loss of electrons
Define reduction in terms of electrons
Reduction is the gain of electrons
Define oxidation in terms of oxidation states
Oxidation is an increase in oxidation state
Define reduction in terms of oxidation states
Reduction is a decrease in oxidation states
Define oxidising agent
A species that accepts electrons and is itself reduced
Define reducing agent
A species that donates electrons and is itself oxidised
What is an electrochemical cell?
A cell that uses the electron transfer during redox to produce electrical energy
What are the two most important factors when setting up an electrochemical cell?
A salt bridge
The species being reduced is on the right hand side
What is a salt bridge?
A strip of filter paper soaked in saturated potassium nitrate that allows ions to flow through it
Define cell potential
The difference in electrode potentials of the two half cells
What are the standard conditions?
298K
1 moldm-3
100kPa
When do we get a positive reading on the voltmeter?
When the positive electrode is connected to the positive terminal of the voltmeter
What is the standard hydrogen electrode?
The primary measuring standard of half cell potentials under standard conditions
What is the electrode potential of SHE?
0.00V
By definition
Why is platinum used as an electrode?
It is inert so won’t interfere with the reaction
It conducts electricity
Define standard electrode potential
The e.m.f of a half cell compared with a hydrogen half cell.
Measured at 298K, all solutions have a concentration of 1 mol dm-3 and all gases have a pressure of 100kPa
Where is the hydrogen half cell in the IUPAC convention?
Left
What should be included in the IUPAC convention? (5)
Phase boundary
Salt Bridge
Species with highest oxidation state closest to salt bridge
Positive electrode on right
Negative electrode on left
More reactive metals will have..
More negative E values
More reactive non-metals will have…
More positive E values
Formula for E
E = RHS - LHS
