Physical Chapter 8: Electrode Potentials & Cells Flashcards
What is an electrochemical cell?
A system where two different metals dipped in salt solutions of their own ions are connected by a wire.
What two reactions must always take place within an electrochemical cell?
Reduction & Oxidation
Are the reactions that occur at each half-cell reversible?
Yes
What are the equations at each half-cell in an electrochemical cell?
Half-equations
What way will the half equations in an electrochemical cell be written as?
Reduction in the forwards direction
What are electrode potentials measured against?
Standard Hydrogen Electrodes
What is standard electrode potential defined as?
The standard electrode potential of a half-cell is the voltage measured under standard conditions when the half-cell is connected to a standard hydrogen electrode.
What does an electrochemical series tell you?
Relative reactivity of metals.
What do more positive electrode potentials mean for the substances involved?
The Left-hand substances are more easily reduced
The right-hand substances are more stable
What do more negative electrode potentials mean for the substances involved?
The right-hand substances are more easily reduced
The left-hand substances are more stable
How do you use Electrochemical series to calculate standard cell potentials?
Ecell = Ereduced - Eoxidised
What are the conventions when drawing an electrode cell diagram?
The most negative potential goes on the left
Oxidised forms go in the centre of the diagram
Things in different phases are separated by a single line
Salt bridge is shown by a double line
How can you use electrode potentials to figure out if a reaction will happen?
For any feasible reaction, Ecell will be positive.
What are electrochemical cells often used as?
Batteries
What does it mean if a battery is rechargeable?
A current is supplied to force electrons to flow in the opposite direction & reverse the reactions
