Click the image to run the resource

What is this?

This is an Open Educational Resource designed to summarise key concepts in entropy and free energy that are required for entry to an undergraduate course. The resource is designed for first year undergraduates or able A-level students in mind and it revisits ideas from A-level. It also begins to show how they are applied early in a University course. The resource was created as part of The Royal Society of Chemistry’s work under the National HE STEM Programme to help bridge the gap between the knowledge expected in a first year undergraduate course and the knowledge gained at A-level.


Learning Objectives

On completion of this activity you should be able to:

  • Relate entropy to the temperature and state of a substance
  • Calculate ΔS for the system and surroundings
  • Calculate ΔG
  • Use ΔS or ΔG to predict whether a process will be spontaneous
  • Describe the limitations of ΔS or ΔG for predicting whether a reaction will occur
  • Appreciate the connection between entropy and the distribution of energy between quantised energy levels in the system.

Previous Knowledge

It is anticipated that users will have some knowledge of A-level chemistry before undertaking the activity. This resource is designed to revise A-level concepts but, even with good subject knowledge, there should also be some material here students are unfamiliar with. This resource is not designed to support any specific A-level specification but may also be used in schools to aid independent study where appropriate.


How was this resource designed?

These resources were designed to be used either by able KS5 students or students at the beginning of their undergraduate course. Some of the concepts that appear in the resources are from A-level courses, some of the concepts might be found in the first year of a university course. The resource wasn’t designed to replace teaching of either but to give students an idea of the things they ought to study themselves before starting a course that builds on these principles. I went to a lot of effort to work with a range of teaching staff at Bristol and at Bath. The idea was to come up with a resource that shows where the story has come from and where it is going to next. I couldn’t keep everyone happy but I’ve created something that hopefully sits in both the world of undergraduate chemistry and “Planet A-Level“!

This OER has been created in Articulate and is made available as an interactive learning object for your VLE. The associated PowerPoint file may also be useful for learning and teaching


Related Resources

There are currently 3 other resources and this resource builds on some of the ideas presented in the activities on dynamic equilibria.


Is it perfect?

No! There are some known and some unknown errors. At some point I will republish but it’s a bit of a mission so want to build up more errors before I go in and fix them all. Some errors just can’t easily be fixed and are a result of the buggy way that Articulate interprets PowerPoint’s motion path animations.

Is the chromatography example for a non-spontaneous process misleading? Is the probability approach to entropy misleading? (again I’ve tried to balance a number of different techniques here – I know about the problems associated with teaching entropy from this angle but I decided on using it but trying to encourage criticism of the model)

All the resources are from the same generation. The fact that not all the numbers reflect this is the result of a typo.

.. if you find other errors please let me know in the comments!


Can I run this on my own machine / VLE?

Yes you can.  Once unzipped on your VLE, the file you need to link to is “player.html” in each resource’s root folder. It will run directly from a local machine but some of the linked resources will not display correctly.

Here is the original zip file which can be unzipped to your VLE:

If you want to use / adapt the PowerPoint it’s here. Some of the animation / transparency had to be faked with layered slides .. if you delete the upper layers, the base layer should look like the one in the resource.



This resource is copyright The Royal Society of Chemistry but licensed under Creative Commons Attribution-Non Commercial-ShareAlike 2.0 (CC BY-NC-SA 2.0). Internal content licenses are referenced at the end of the resource.