Electrochemical cells

Practical work based on electrochemistry offers opportunities for learners to investigate the thermodynamic feasibility of reactions and apply their knowledge of the reactivity series. 

Chapter titles: 00:15 Introduction; 01:30 Electrochemical cell set-up (including animation); 02:15 Investigating redox reactions (microscale set-up); 03:23 Taking measurements; 04:09 Animation showing cells in microscale; 06:18 Cell diagrams; 07:43 Investigating concentration.

Teacher notes

Full teacher notes are available in the supporting resources booklet, including ideas for how to use this video and the supporting resources as part of your teaching. 

Technician notes including the equipment list and safety notes are provided. If you are planning to carry out the practical in the classroom, you will need to carry out your own risk assessment.

For guidance on how to use this practical with learners aged 14-16, see A micro approach to electrochemical cells yields big learnings.

Prior knowledge 

The video and resources assume the following prior knowledge:

• Metals can be ordered into a reactivity series.
• The more reactive metal is a stronger reducing agent.
• Zinc is more reactive than copper.
• Oxidation and reduction defined in terms of electron transfer - OIL RIG.
• Electrons are negatively charged and move from a negative terminal to a positive terminal.
• ∆G is negative for feasible reactions.

Learners could be directed to our 14–16 video with supporting resources Electrolysis of aqueous solutions, for revision prior to this practical.

Common misconceptions

Be aware of misconceptions learners may have around this practical, for example:

• Only metals can be placed in the reactivity series.
• Large quantities of solutions are needed.
• A sizeable current is flowing when we measure the voltage.
• How the salt bridge works.
• Surface area of the metal will change the electrode potential.

This article Redox: reducing difficulties, looks at common misconceptions more closely and suggests strategies to address them.

Further practical activities

The demonstration The oxidation states of vanadium explores different colours of different oxidation states of the transition metals and continues to develop the knowledge that electrode potentials can be used to help predict the course of redox reactions.

Our exhibition chemistry video Nailing corrosion demonstrations looks at rusting from an electrochemical perspective.