Hey, today he is still very funny. I felt very enthusiastic in the class of this German teacher to study more and more about chemistry. One thing that he always did in the beginning of the class is asking: "Mau belajar apa kita sekarang?" [What we are going to learn this time?]. Many students answered him in a kidding way and finally Ricky, my friends shout "Chemistry!" and he said with smile "Benar.....". Well so now we continued the lesson about Acids and bases.
I remember about Bronsted (Denmark) -Lawry (England) theory of acid and bases are:
acid: proton donor
bases: proton acceptor,
while in the Lewis theory, the acid is an electron acceptor and base is electron provider.
He also expained clearly about the concept of Auto ionization of water:
H2O<>H3O+ and OH-
Strong acids are the acids that give up all their free electron to form the compound. For examples: HCl, H
2SO4, they can disassociate perfectly in the water.Extent of disassociation
Ka= [H3O+][A-]/[HA][H2O]. Because the extent of [H2O] is too small, then the equation will become:
Ka= [H3O+][A-]/[HA]
and for the scale of Ka, pKa=-log Ka.
And then for the Reaction rate, the speed of amount change over time in a chemical reaction.
Fast reactions for example oxidation in fruits, fireworks, explosion '
Slow reaction for examples, corrosion, and decomposition
The chemical changes in reactions that we can observe are: the color, the volume, and the conductivity.
So, the Reaction Rate R=[A]/t
and for instantaneous Rate limit of dA/dt.
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