[OCHEM] - 2011 Oct 05

The above is true, if you're looking at the bonding at this exact moment.

This is because anions in the sp2 orbital are more stable than anions in the sp3 orbital. (If you were to look at the conjugate bases of these molecules.)

A more stable conjugate base = it is more likely to form.

Therefore, the acid is more acidic.





B is more acidic.
-The biggest difference between the two carboxylic acids is the Chlorine atom attached. (Chlorine is a highly electronegative atom, and it's close to the acidic functional group)
-Both of these molecules can get a resonance stable anion. (As in the previous example)


Being close to the acidic functional group allows for an "induction effect". (Inductive effect).
-Electronegative atom (Cl) pulls electron density towards self
-Highly electronegative atoms polarize bonds, pulling e- (electron) density towards themselves.
-Groups that withdraw e- density will help stabilize conjugate base. (Therefore increasing acid strength)


-Inductive effects are stronger the closer the EN (electronegative) atom is to the acidic functional group
-Inductive effects work through sigma bonds


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We also began looking at Redox, but firstly, go to
-http://www.chem.ucalgary.ca/courses/350/index351-f11.html
-"e text website" (or whatever)
-useful concepts
-oxidation/reduction

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Oxidation & Reduction in Organic Chemistry
(another handy tool for e- bookkeeping)

In organic chem....
-Oxidation = loss of e-
-Reduction = gain of e-

This works well for inorganic ions. (Cr 6+ reduced to Cr 3+)
but most organic compounds are uncharged and the gain/loss of e- is not obvious.

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In organic chem.....

Oxidation (@ Carbon, usually)	Reduction (@ Carbon)
decrease in # of C-H bonds	increase in # of C-H bonds
increase in # of C-O bonds (more generally, increase in # of bonds to atoms with higher EN than C)	decrease in # of C-O bonds (more generally, decrease in # of bonds to atoms with higher EN than C)

And then yeah Carries on to the same thing at the beginning of Oct 7. Enjoy!

Uh..?

Red is in the most acidic?

and neither cause they're the same? o.O? Unless I'm looking at this wrong.

Lalala

Karma wrote:Uh..?

Red is in the most acidic?

and neither cause they're the same? o.O? Unless I'm looking at this wrong.

Lol, yes, you are correct. xD But right now we don't really care between blue or red which one is more acidic. But you are definitely correct.

So sp1 is more stable then sp2 and 3 right?

In this case there are no sp hybrid orbitals, so probably not. xD

When we're talking about stability in these two cases, between the sp2 and the sp3, we're talking about where the anion of the conjugate base would be. The -'ve would be more stable at red or blue, because they would be added to the sp2 orbital.

At purple, it would be added to sp3 :0


And dood, these are just my notes from class on Oct 5, haha

^


Awkward spacings due to laziness to change canvas size.. Obvious. Lol

Well dood xD I like looking and figuring things like this out and what not.

Dood


Be a chemist. :D Chemistry is fun!

Well...

I can draw Lewis diagrams...

Good!

These are called 'Line-Angle Diagrams' and IB doesn't like them... So don't learn them-- yet!

Karma wrote:So sp1 is more stable then sp2 and 3 right?

I should have answered this.

Yes, sp orbitals are more stable with handling the charge, like an anion, because there is more s character than p character.

sp - 1 part s, 1 part p
sp2 - 1 part s, 2 part p.. etc

and the sp2 is actually sp^2 (exponent two, squared)

Ohohoh I see o.O

How come frost forming on a window is considered an exothermic reaction?

This is because either liquid or gas turns into a solid phase. We all are aware that gas has the most energy and next is the liquid phase (the molecules move a lot, remember drawing those gross pictures you drew? Gas has the most space between the molecules, and they're moving fast, liquid kinda moves and there's kinda space, solid is pretty much unmoving, and they're all positioned nicely)

Well in this case

liquid + energy --> gas (endothermic reaction)
gas --> liquid + energy (exothermic reaction)

Because we would need more energy to "move" those liquid molecules as you can picture it, so when liquid--> gas, it needs energy, thus endothermic.

gas has lots of energy, so when it becomes liquid it "slows down", in a sense. Thus, releasing energy, and therefore exothermic.

Similarly with solid

solid + energy --> liquid (endothermic)
solid + lotsaenergy --> gas (endothermic)
liquid --> energy + solid (exothermic)
gas --> lotsaenergy + solid (exothermic)

There are some values somewhere, but this is the general idea

I see. I see. Okay, thanks dood. I think I get it now. What was Hess' first name?

Germain Hess.

OH MY GAWD.