If you need some additional resources for o-chem, the following website has helpful information on mechanisms and reactions:
http://www.chemhelper.com/mechanisms.html
To review for the test, we will be making a study guide in class which will summarize the reactions we have covered. These will include reactions with
1-Alkanes
a. radical substitution (know mech)
b. dehydrogenation
2-Alkenes
a. hydrogenation
b. addition of acids (H-X) and halogens (X2) [know mech]
c. polymer addition (to be covered tomorrow) [know mech]
3-Halogenoalkanes nucleophillic addition reactions
a. primary [SN2]
b. secondary [SN1 and SN2]
c. tertiary [SN1]
4-oxidation of alcohols [know reagents used]
a. primary --> aldehyde --> carboxylic acid
b. secondary --> ketone
c. tertiary --> no rxn
5-polymers (addition rxns of alkenes) to be covered tomorrow
a. margarine
b. ethene --> ethanol
c. plastics (PVC)
To get the most out of tomorrow, you should start going over your notes and categorizing the reactions under those 5 titles. Post any questions on the blog. You should be looking over these reactions nightly. This is organic chemistry, it's not supposed to be easy. Do not expect yourself to understand it and remember it if you only look at it in class. It will require time outside of class.
See you tomorrow,
Ms. Marostica
10 comments:
http://www.chemhelper.com/images/pictures/prop1.gif
this is a link to a propagation step on that website you gave us. i was wondering what happens to the Cl radical in this reaction. I know it steals the H to get its electron, creating another radical product, but is there a second product of HCl? and if the arrows mean the transfer of electrons, why aren't they pointing in the other direction on this diagram?
thanx =)
Yes, the Cl radical takes the H and makes HCl. They simply left this product out on this particular website. This is most likely because the HCl does not contribute to the propagation of the radical reaction; however, you will need to include it on the test, just as you have it in your notes.
I think you're referring to the arrow pointing towards the alkane when the Cl radical takes the H. If this is the case, this is showing that Hydrogen leavs with the electron it came in with and the electron the carbon donated to the bond goes back to the alkane. This arrow is showing the homolytic fission.
ms. marostica, i dont seem to understand whats the difference between 2-butene and but-2-ene.
No difference I think edward. But on the free response, lists the answers to steps 2 and 3 of part e) as requiring (sulferic) acid. I assume that just means the H+ we always see?
Also, in d) it says award 1 for correct equation starting with 1-butene. But it tells us to start with 2-butene. And it doesn't list the reaction type, unless that part got grouped in with e) on accident.
Correct. There is no difference. Just a different way of naming.
"But on the free response, lists the answers to steps 2 and 3 of part e) as requiring (sulferic) acid. I assume that just means the H+ we always see?"
Yes, the H+ comes from sulfuric acid.
"Also, in d) it says award 1 for correct equation starting with 1-butene. But it tells us to start with 2-butene. And it doesn't list the reaction type, unless that part got grouped in with e) on accident."
The answers provided are from the IB markscheme. This outlines how to distribute points. IB will award half credit if you start with the wrong reactant: 1-butene.
The reaction type is listed as "addition" It's the last word on part (d).
so for the free radical ones... if it can form both tertiary and primary, would you need to write both or just the more stable one? I know with Br, its way less likely to have the less unstable config. than Cl, so do we need to take that into consideration?
You won't have to deal with any problems that have you decipher between secondary and tertiary radicals.
mk sweet. thanks =)
What do we need to know for the mech. for the polymer addition?
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