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.
Link this topic to organic reactions since a lot of them are actually acid/base reactions. That is, there is one species that’s electron rich and one that’s electron poor.
There are only about three key principles that they need to know from this topic at first year level. All of it comes back to understanding equilibrium and buffers. Because if they understand buffers (which involves understanding weak acids and weak bases, conjugate acids, conjugate bases, equilibrium, Ka, Kb) then they can immediately understand titrations and all the concepts that they need because they’re encompassed in the concept of a buffer. If they’re dealing with either biological or chemical systems they’ll deal with buffers.
Use everyday examples. A great question to have at the end of your lecture would be ‘What is reduced when my bike rusts?’ They might understand that their bike rusts, but what is reduced? Oxygen and water are reduced. But we don’t see the reduction, we just see the iron changing. You have done your job well if someone asks the question ‘What is reduced when my bike is oxidised?’
Use drugs as an example of the relationship between how much of a species is protonated and how much is non-protonated. This is an equilibrium process. For a carboxylic acid drug, if it’s protonated it’s not ionic, if it’s not protonated it’s anionic. And if it’s going from gut into blood for example, whether or not it goes through the membrane will depend upon the pH of the system.
Relate equilibrium to students’ own experience of strong versus weak acids. For example, you can put vinegar on your fish and chips but not HCl. From high school they might have an understanding that vinegar is a weak acid compared to hydrochloric acid, but they never knew why. And you could then show them that with equilibrium, this is why.
You can liken teaching chemistry to hacking your way through a forest. It’s a lot of detail, and you can’t expect students to do the hard work of fighting their way through the forest or the jungle, unless they have a global view of where they’re going. Keep going back to applications in the real world. How is it that geckos can crawl up a wall, and sit on the ceiling without falling off? How is it they’re able to stay there with gluey legs or something? How do they maximise the attractions between the molecules in their feet and the molecules in the ceiling?
In organic chemistry for anything that's structure-based it’s imperative that they understand molecules are three dimensional - that they have a spatial requirement. And you can talk about the actual real-world outcomes of that, like drug design and penicillin structure and things which might be what they're actually interested in.
There could be five “different” reactions, but actually they are the same core mechanism. If they can identify an electrophile and a nucleophile and how they get together in a particular context, then they understand all five of the reactions and another 55 too, if they choose to. The ultimate goal is that they have a skill-set, a set of tools, that allows them to meet any reaction, even reactions they have not seen before, and apply the concepts, use the tools, and get a handle on what is actually happening.
