Start to flag the concept of equilibrium early when teaching other topics, saying this is the concept of equilibrium we’ve got to come to later. So students start to understand how it’s all interlinked, rather than it being a lone, odd concept?
Compare the material to what they might be learning in physics. For example, in Le Chatelier’s principle, a phrase like ‘counteract the change’ is similar to Lens’s Law in physics for electromagnetic induction. So maybe if students have a better grip of that they can see similarities there. It’s trying to draw that bridge. If the students aren’t doing physics you can always draw something from maths or something from biology.
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.
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.
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.
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.
Use several real life examples with different ways of causing the equilibrium to shift. Swimming pool chemistry:
HOCl can enter the cells of undesirable organisms to kill them, but OCl- can’t, hence if the equilibrium is too far to the right it won’t act effectively. If you add acid (say HCl) the position of the equilibrium shifts to the left, producing more OCl-. That’s partly why the pH of the pool is important.
You rarely see organic reactions split up into two half equations. You could show the link between redox and organic chemistry by getting them to write the half equations for reactions like the oxidation of an aldehyde, ketone or alcohol with permanganate, for example. You want them to realise that it goes from purple to colourless then they have to write it out.
