Chapter 11-specific PCK
PCK1101
Visualising dynamic chemical equilibrium
With reference to Learning module 1101: Visualising dynamic chemical equilibrium
I am committed to the belief that good quality visualization at the molecular level of chemical phenomena is a crucial component of meaningful understanding in chemistry.
The cultivation of quality imagery in our students presents a massive challenge. First, there is the question of what constitutes good visual imagery for a particular phenomenon, because I almost find that other people’s images are different in some way from mine.
And then there is the pedagogical challenge of how to develop good quality images of the nature and behaviour of atoms, ions and molecules.
We all use words to describe phenomena, but oh to be able to see what mental images those words conjure up.
You are rambling, Prof Bob …..
The cultivation of quality imagery in our students presents a massive challenge. First, there is the question of what constitutes good visual imagery for a particular phenomenon, because I almost find that other people’s images are different in some way from mine.
And then there is the pedagogical challenge of how to develop good quality images of the nature and behaviour of atoms, ions and molecules.
We all use words to describe phenomena, but oh to be able to see what mental images those words conjure up.
You are rambling, Prof Bob …..
Well, where I am going is that I find it difficult to visualize reactions in a reaction mixture proceeding simultaneously in the “forward” and “backward” directions. I know what it means, but I have trouble with a mental picture.
Things are much easier for me when I refer (defer?) to my view that all chemical reactions are the result of competitive processes: acid-base reactions are competition for protons; oxidation-reduction reactions are competition for electrons; complexation reactions competition for ligands.
Now the world opens up for me!
I can well imagine that in an aqueous solution of acetic acid, water molecules are continuously “winning” protons from aquated acetic acid molecules, and that simultaneously aquated acetate ions are “winning” protons from hydroniums ions.
Yes, it is easy for me to imagine protons being “grabbed” and being pulled from one species to another. Hence the analogy that I use in module 1101: Visualizing dynamic chemical equilibrium.
Yes, I am aware that proton transfer is (or results in) the reaction represented by the written chemical equation.
But it helps me to see it that way. Maybe some students will, also?
Things are much easier for me when I refer (defer?) to my view that all chemical reactions are the result of competitive processes: acid-base reactions are competition for protons; oxidation-reduction reactions are competition for electrons; complexation reactions competition for ligands.
Now the world opens up for me!
I can well imagine that in an aqueous solution of acetic acid, water molecules are continuously “winning” protons from aquated acetic acid molecules, and that simultaneously aquated acetate ions are “winning” protons from hydroniums ions.
Yes, it is easy for me to imagine protons being “grabbed” and being pulled from one species to another. Hence the analogy that I use in module 1101: Visualizing dynamic chemical equilibrium.
Yes, I am aware that proton transfer is (or results in) the reaction represented by the written chemical equation.
But it helps me to see it that way. Maybe some students will, also?
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