History of acids/bases. (1 Viewer)

[ND]

"outline the historical development of ideas about acids including those of:

- Lavoisier
- Davy
- Arrhenius"

"gather and process information from secondary sources to trace developments in understanding and describing acid/base reactions"


Does anyone have separate notes on these two dotpoints? I've just got one set of notes, including conjugates (which i'll cut out if the 1st q comes up in the exams)... What are the differences in your notes?

 

[inasero]

i see what you mean...the first dp merely requires you to talk about developments objectively and independently of each other

the second one requires you to investigate how scientists developed upon the works of previous theories due to shortcomings in ability to encompass different substances....

eg lavoisier said that acids contain oxygen throough his limited obersvations of acidic oxides while davy demonstrated that this was noy necessarily so (as HCl demonstartes) and because there were plenty of substances which contained oxygen and YET were not acidic (ie the basic metal oxides)....

As a consequence Davy revised this theory and said that acids were substances wihhc contained replacable hydrogen (replaced with metals). The shortcmonigs of this definitoiin are that it did not take into due consideration the role of the solvent in acid-base reactions

Arrhenius proposed that acids ionise IN SOLUTION to produce H+, while bases ionise in solution to produce OH-. This definition also was limited cos there were some basic metal oxides which didn't contain OH-

Lowry-Bronsted said that an acid is a proton donor and a base is a proton acceptor, thus doing away with the problem of trying to ascribe basic/acidic properties to particular chemical species, but rather, explaining in terms of structure. It is important to note that the above are all theories. As such no particular definiton (including B-L) is completely able to define all acids and bases comprehensively.

After this came G.N.Lewis with his electron pair exchange theory but you're not required to know that for the new syllabus.

Good luck ND~

 

[ND]

Thanks.

 

[Frigid]

you might (or might not) wanna remember these mnemonics:
Lazy Oxen Dun Hatch - Lavoisier Oxygen, Davy Hydrogen.
Angry Hens Pecked the Little Brown Dog - Arrhenius Hydrogen Proton, Lowry-Bronsted Donor.

 

[inasero]

yeeeeeeeessssss ooooookkkkk then.....

 

[Frigid]

LoL@inas...
bro, sometimes chem can get boring... therefore need to make it interesting...
newais, mnemonics are quite easy to remember and decode.

 

[crazylilmonkee]

studying from ur notes at the moment frigid!
thanks

i just stuck the peeps contribution on the wall and i have LDAB stuck in my head..

 

[Frigid]

hahaha... mister craig seawright should be proud that his tute student help other students who in turn will help other students...
hail to mr. seawright (aka GoD)!

o btw, monkee, remember reading is not enough... do some past papers and read some marking guidelines...

 

[crazylilmonkee]

yes sir

 

[ND]

Originally posted by Frigid
you might (or might not) wanna remember these mnemonics:
Lazy Oxen Dun Hatch - Lavoisier Oxygen, Davy Hydrogen.
Angry Hens Pecked the Little Brown Dog - Arrhenius Hydrogen Proton, Lowry-Bronsted Donor.

Hahah, interesting.

 

[inasero]

sometimes chem can get boring... therefore need to make it interesting...

agreed there

hmmm i think year 10 maths with Boros was...er..."enlightning"
mnemonic to remember the four trigonometric signs in each quadrant: "All (All) Sluts (Sine) Take (Tan) Cash (Cosine)"...I won't be forgetting that one too soon~
And the standard "OILRIG", An Ox, Red Cat....meh

 

[ND]

Hmm i've been sitting here for 2 mins trying to work out what OILRIG is.... what is it?

 

[Lord Ac]

oxidation is loss (of electrons)
recduction is gain (of electrons)



Ac (yay! I knew it )

 

[ND]

Ohhh, haha do you really need a mnenomic for that?

 

[phenol]

VSEPR

Valence Shell Electron Pair Repulsion

Vitality Sign Ending Please Resuscitate

cheers Gerald

 

[toknblackguy]

thanks inasero
very good explanations