Electrochemical Cells Flashcards
What is meant by electrochemical series
List of electrode potentials in numerical order
Salt bridge
Completes the circuit
Allows ions to flow
KNO3
Standard hydrogen electrode
Comparison tool
What the standard conditions for standard hydrogen electrode
100kpa - pressure
298k- temperature
[H*]- 1.00 moldm^-3
Why do we use standard electrode potential
Cheap
Quick
Good reference
Pt- is expensive
Why is platinum used in standard hydrogen electrode
It used as it is un reactive
Metal good conductor of electricity
Describe and experiment the student does to show that the standard electrode potential for the TiO^2+(aq)/Ti(s) electrode is -0.88v- 6 marker
Step 1- preparing solution
1a) weigh the solution
1b) dissolve in and add your acid
1c) transfer to volumetric flask and make up to the mark
Step 2) set up the cell
2a) piece of Ti immersed in TiO2+
2b)connects solution with salt bridge
2c) connect metal with voltmeter
Step 3- measurements and calculations
3a) record voltage
3b) Ecell=Erhs-Elhs
how to calculate emf values
E= Erhs -Elhs
Red-oxi
Doesn’t apply with standard hydrogen electrode
When is a reaction feasible
When the EMF VALUE is positive
What is oxidising agent in terms of electrons
Gains and electron
Electron acceptor
What is reducing agent in terms of electron
Loses electrons
Donates them
More -Electrode negative
More reactive
More easier it is to be oxidised
Equilibrium shifts to left
More electrode positive
More positive
Easy to reduced
Equilibrium shifts to right
Exam question ask for weakest reducing agent
Look at the value with the greatest +E*
Then check for the one which is not oxidised
Exam question asked for the weakest oxidising agent
Look at the value with the greatest -E*
Then pick one which is likely to be reduced
Reducing agent
Oxidised -ve
Oxidising agent
Reduced
+ve
