Here's why I like ethanoic acid - Daniele Gibney

Molecules are central to chemistry. That’s obvious, you might say, but in focusing on covering the specification it can be easy to forget about all the fascinating substances that exist and the stories they have to tell. Looking at a molecule and examining the things it is used for, the things it can do, and just its basic properties can make the subject come alive. It could really help your learners’ understanding, too.

Ethanoic acid 

I like ethanoic acid. Literally – salt and vinegar is my favourite crisp flavour – but also as a model, if you will, for the message of this post. This under-hyped, go-to weak acid and oxidation product is in fact a route to checking understanding of fundamentals of chemistry, not to mention to linking specification content to real-life experience.

As the latest Molecule of the month entry will tell you, oxidation of alcohol to form ethanoic acid is the reason wine tastes a lot less pleasant a week after opening. This reaction has also been used in breathalysers. These are real-life applications of a staple A Level Chemistry reaction. Using examples like these in teaching will show learners the relevance of the chemistry that they are studying, and hopefully help the content to stick.

Ethanoic acid is also a great link between inorganic, physical and organic chemistry. It is an organic molecule that takes part in organic reactions. It is also an acid, undergoing all the prototypical reactions with carbonates, oxides and so on. But it is a weak acid, which prompts us to think about equilibrium, and it is water-soluble, which prompts us to think about hydrogen bonding.

The list goes on, right down to the basics. Ethanoic acid has a molar mass, a molecular formula, an empirical formula and a structural formula. It contains sigma and pi bonds. It contains two different carbon atom geometries. It’s hard to find an area of the specification that can’t be linked to this molecule.

Synoptic thinking

These qualities of ethanoic acid are, of course, not unique. Pretty much any chemical can be used to tell interesting stories and make the specification come to life. And certainly every chemical can be used to review understanding about the basics of chemistry, and to make links between different areas of the specification.

Being able to think flexibly, tying different areas of chemistry into a given context, will be an important skill in the assessments for the reformed specifications. In teaching these linear qualifications, taking a close look at different aspects of one molecule can be a good way of keeping content fresh, and developing a synoptic understanding of the specification. Discussions like this can be used formatively, to drive consolidation or revision sessions. What areas of the specification can learners readily bring to mind? What topics are they not thinking about, and might they need a bit more support with?

I’m looking forward to hearing Dr Simon Cotton – who wrote the Molecule of the month piece cited above – speak at SCInopticity on 16 June 2016. He will be giving suggestions on how to take chemistry ‘beyond the textbook’, to enrich chemistry lessons and develop skills to apply knowledge in new situations. He’ll be talking about numerous, even more interesting, molecules relating to things like explosives, food and perfume. This talk is part of a programme supporting synoptic thinking, as well as practical and mathematical skills, across the sciences. I hope you’ll be able to join us there. 

About the author

Daniele Gibney - Subject Specialist - GCE Chemistry

Daniele has been with OCR as a GCE Chemistry Subject Specialist since March 2014. In that role she is the first port of call for teachers who have questions about specifications or assessment, and she loves getting into exchanges of ideas about how to introduce particular topics in the classroom, or embed the teaching of certain skills. Daniele has a background in educational publishing, having worked on textbooks and support materials for science education from primary to post-16.

When not having conversations about how brilliant chemistry is, she is usually either trying to keep up with her Open University degree in Social Sciences, making things out of yarn, or watching rugby or Formula 1. Frequently all three at once.