An understanding of electrochemistry allows us to predict the feasibility of reactions (useful), prevent corrosion in metals and build a fuel cell (also useful), amongst other things. Everything relates back to redox chemistry, and I emphasise this because you will need to keep going back to first principles to make sense of it all.
Oxidation / reduction / oxidising and reducing agents are easily confused!
Understanding electrode potentials
- what is an electrode potential and how does it relate to a redox reaction?
- what is an electrochemical cell?
All the key terminology explained in a super clear way!
Determining the potential difference of an electrochemical cell
We can link any two half cells together to form an electrochemical cell and then use a high resistance voltmeter measures the maximum potential difference, EMF or Ecell.
Predicting the feasibility of redox reactions
If we take a pair of half reactions we can use the standard electrode potential for each to determine which will form the oxidation half cell and which will form the reduction half cell.
If we know this we can predict the direction / feasibility of the reaction.
Understanding the relationship between the potential difference for an electrochemical cell and Gibbs energy
The spontaneity or feasibility of a reaction can be described by both a positive Ecell⦵ value or a negative value for the change in Gibbs energy, ΔrG⦵, so is it is no surprise that the two are mathematically related.
Using the relationship between potential difference and Gibbs energy to calculate a value for the equilibrium constant, K
The chemistry of corrosion
The chemistry behind the rusting of iron takes place via a series of half reactions that take place in the iron itself and a water droplet – find out more here …
The chemistry of batteries
Modern storage cells (batteries) can be divided into the non-rechargeable kind (primary cells) and the rechargeable kind (secondary cells).
This is a quick introduction to primary cells focusing on what you need to know for A level.
The chemistry of fuel cells
Fuel cells commonly use the reaction between hydrogen and oxygen to produce a voltage, with water being the only waste product.
There are acid and alkaline fuel cells – find out all about them here!
Electrolysis of molten ionic salts
Electrolysis of molten ionic salts produces the pure metal and non-metal element.
Review your understanding of the redox reactions that take place …
Electrolysis of solutions
Electrolysis uses electricity (energy) to drive a non-spontaneous reaction which is useful for recharging batteries, splitting water to make hydrogen and in producing chlorine from brine.
Using the Nernst equation to calculate the electrode potential of a half cell
What happens to the electrode potential if we change the concentration or the temperature?
We can make a qualitative judgement using le Chatelier’s principle but if we want an actual quantitative, numerical answer, we need the Nerst equation.
Electrochemistry exam question practice
Exam style questions written to stretch and challenge your understanding and analysis skills, with A* perfect answers, exam tips and tricks 😍