Electrode potentials and cells Flashcards
What are electrochemical cells made of?
two different metals dipped in salt solutions of their own ions and connected by a wire
What is EMF?
cell potential, it is measured using a voltmeter
How do you measure how easily a metal is oxidised?
using electrode potentials
In a conventional representation, what does the vertical double line represent?
salt bridge
In a conventional representation, what does the single vertical line represent?
things in different phases/states
Which half cell goes on the left?
the one with the most negative electrode potential
How do you calculate cell potential?
Cell potential (right hand side) -cell potential (left hand side)
What factors affect electrode potentials?
changes in temperature, pressure and concentration
What are the standard conditions?
concentration of 1.00mol/dm^3
temperature of 298K
pressure of 100kPa
What electrode is used in a SHE?
platinum electrode
What is the electrode potential of a SHE?
0.00V
What is an electrochemical series?
long list of electrode potentials for different electrochemical half-cells
In an electrochemical cell, is the half equation with the more negative electrode potential in the direction of oxidation or reduction?
oxidation
In an electrochemical cell, is the half equation with the more positive electrode potential in the direction of oxidation or reduction?
reduction
How can you predict whether a redox reaction will happen and what direction it will go in?
- Find the two half-equations for the redox reaction, and write them both out as reduction reactions.
- Use an electrochemical series to work out which half-equation has the more negative electrode potential.
- Write out the half-equation with the more negative electrode potential going in the backwards direction (oxidation) and the half-equation with the more positive electrode potential going in the forwards direction (reduction)
- Combine the two half-equations and write out a full redox equation.
