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.
Use demonstration or simulation of how both forward and reverse reactions occur up to and at equilibrium in several mixtures. The PhET simmulation below shows both reactions are happening, even though concentration of reactants and products isn't changing.
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.
Demonstrate a reaction that occurs within the time frame of your lecture. Start it at the beginning of the lecture, and then go back to it in the middle and at the end to show what has happened. For example, you can use copper in silver nitrate solution.
If you look at the resources - students’ have textbooks, they have electronic media, they have Sapling. They can do the problems in their own time in a guided way with something like Sapling. All we as lecturers have to do is give them the framework to solve the problems. If you set up the framework for them and let them go away and use that framework and learn how to solve problems they’ll teach themselves. So it’s a matter of giving them that framework and it’s the buffers that are the framework of it all.
If you look at the resources - students’ have textbooks, they have electronic media, they have Sapling. They can do the problems in their own time in a guided way with something like Sapling. All we as lecturers have to do is give them the framework to solve the problems.
Put zinc metal in copper sulphate solution and record it with the visualiser. Have it running as you talk about the push and pull of electrons. Then bring it up and say, ‘look what’s happened here, the zinc has rusted’. Students make more of a link when they see things being visualised. The oxidation of metal has a very visual impact on them. But then, they might forget about the reduction side, so you need to remind them of it.
