Physical Chemistry

Physical chemistry

Link to Related Topics

Interconnect equilibrium with other topics – acid-base, reaction rates etc. You can introduce part of the topic of weak and strong acids and then do a bit of equilibrium, just enough to make sense of it.

Teach Qualitative Cocepts First

Get students to have a qualitative understanding before they apply it. Teach the topic qualitatively and then they can realise that they can do calculations with it. Q and K would come later, after they have the qualitative understanding.

Differentiate Q and K

Start by defining the Q and K, and saying that Q is your tool. K is over here and it doesn’t change, but Q is your tool to assess how close we are to K in terms of the system.

Red Flag for New Words

Use red flags on lecture slides every time a 'new' defined word is used, to reiterate the meaning which is different to the meaning they might have encountered before. Even the word ‘equilibrium’ which has a meaning in the chemistry context and an everyday meaning. There will be literally a red flag on the slide.

Repackage Into Simple Wording

Le Chatelier’s principle is quite cumbersome in its wording, so break that down into language that’s easier for students to understand - that’s called repackaging. Repackage of the concept and wording into language which students understand and can relate to. For example, if you heat the system up, both reactions get faster. One gets faster and faster and the other one gets faster and faster. That is good terminology that the students will understand.

Demonstrations With Equations

Use demonstrations with equations concurrently. Use YouTube demonstrations which clearly show what’s happening

Link to YouTube Video: Dynamic Equilibrium

Nitrogen Dioxide/Tetroxide Demonstration

A visual demonstration of Le Chatelier’s principle involves the dynamic equilibrium between nitrogen dioxide and dinitrogen tetroxide gases. Fill a gas syringe with an equilibrium mixture of brown NO2 and colourless N2O4. The effect of pressure is shown by compressing the mixture and observing the change in colour intensity. Similarly, the effect of temperature can be shown by heating or cooling the mixture and observing the colour change.

Link to Previous Experience

It’s really important always to keep going back to links of where they might have seen equilibrium previously, because then they start to get the idea of chemistry topics being interrelated. Even put at the end of each lecture a little problem, for example, ‘how is equilibrium related to acids and bases?’ Even if they don’t understand it yet, just mention it so it’s in the back of their mind when they do learn about that topic.

Discuss in Terms of Concentration

Extend equilibrium to a more general discussion of concentration. If you increase the amount of one reactant, or if you compress the system - all of those things could be considered just as changes of concentration. Rather than splitting them up into different categories of changes of concentration. If you change the concentration of one or more species, there’s a net reaction in the direction that relieves that change. It’s that holistic approach to understanding concentration.

Population Analogy

Use the analogy of populations migrating between adjacent cities.


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