What are the pi and sigma bond structures in benzene and other organics?

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Offline omid

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can you please tell me the structures of pi and sigma bonds in ethane, methane, ethene, benzeneand chloroethane? [:o]
« Last Edit: 26/05/2009 14:05:50 by chris »

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Offline Chemistry4me

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Methane and ethane are sp3 hybrisised, no pi bonds.
Ethene is sp2 hybridised, 1 pi bond, the rest sigma.
Benzene is sp2 hybridised and each carbon has a p orbital. All six are defined as equivalent, so it's impossible to define three localised alkene pi bonds. Each p orbital overlaps well with both neighbouring p orbitals, resulting in two doughnut-shaped clouds.

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Offline omid

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« Reply #2 on: 29/05/2009 13:19:28 »
can you please tell me the structures of pi and sigma bonds in ethane, methane, ethene, benzeneand chloroethane?

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Offline Chemistry4me

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« Reply #3 on: 29/05/2009 23:20:13 »
Why don't you just tell me what you do not understand about my answer to the question and we'll go from there. I think that way you might actually learn something instead of just asking for the answer. [:)]

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Offline omid

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« Reply #4 on: 30/05/2009 16:50:52 »
look please don't be angry [:(].
you did not read my question carefully i need drawn structures of ethane, methane, ethene, benzeneand chloroethane which mentions pi and sigma bonds in them?
if you can please provide me with some accurate sources of information or you can just tell me the drawn structures of them.
thank you

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Offline BenV

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« Reply #5 on: 30/05/2009 17:25:44 »
I've merged these two identical topics - please keep all discussion of one topic to one thread.

Also, if I may express an opinion - you didn't ask for drawn structures before, so you can hardly blame Chemistry4me's reading skills if you didn't get the answer you were after.

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Offline Variola

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Also try doing some of the work yourself.... drawing the structures out etc and trying to figure out where the bonds would be. The structures of the chemicals will be available in any good chem book or online.
Then when you have done that, if you are still stuck them come back and ask for help on specific points rather than just expeting the answer.
It's what I and others have to do.
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline omid

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i've been doing this myself for past two weeks i didnt find anything thats when i joined the science forum and asked for help.
if you dont have the answer then i must say that this topic is not for you and you better stay out of this topic.

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Offline Variola

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Quote
if you dont have the answer then i must say that this topic is not for you and you better stay out of this topic.

Actually I do have the answer as I am currently revising for my chem exam, chemistry is not a science that comes easy to me so I have had to draw out all the structures of the chemicals and compounds I have been looking at... hence I know that the answers are out there if you bother looking for them.
Do some of it yourself and people will be far more inclined to help you, rather than just give you the answers.
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline omid

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look if you don't want to answer my question then please don't bother yourself
infact the time you are using to reply me why don't you use the time to prepare for your chem exam.
and by the way my question was for chemistry4me so just let him reply.
thank you for your help again.

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Offline Variola

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look if you don't want to answer my question then please don't bother yourself
infact the time you are using to reply me why don't you use the time to prepare for your chem exam.
and by the way my question was for chemistry4me so just let him reply.
thank you for your help again.

Why dont you take the time you are spending on here demanding answers to try and do he work for yourself, and I respectfully suggest that it is you who needs to do their revison and not me. C4M has already given you an answer that would enable you to draw it out, people are not here just for your benefit.  [::)] [::)]

Gee how many times can you tell someone!!  [::)] I think I'll give up now.
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline omid

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good for you

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Offline Chemistry4me

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I don't know what structure you are after, does it look like:

b)



OR

is it like:


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Offline Chemistry4me

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You know what? I think you are after the latter in which case:

Ethane



Benzene



Ethene



Chloroethane



« Last Edit: 31/05/2009 00:15:26 by Chemistry4me »

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Offline omid

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thank you
i think the first one is what i m looking for.
thank youuuuuuuuuuuuuuuuuuuuuuu [;D]

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Offline omid

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My qustion is for chemistry4me
can you please tell me the question below;
evaluate the influence of structure and bonding on the course of reaction and explain the follwing;
alkanes undergo free redical reaction.
what i dont understand in this question is the that the word evaluate is confusing me that's why i dont understand that what the question is really asking for??????????????????????

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Offline Chemistry4me

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I think it is asking you to explain why the structure and bonding in alkanes (are you sure it is alkanes and not alkenes?) causes it to undergo free radical reaction.

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Offline omid

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thnx again
yh it is alkAne

                                                                                                                                                                                                                 

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Offline omid

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One more thing can you help me with biology topics as well please.

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Offline Chemistry4me

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Haha, post it and I'll have a look. But I make no guarantees.

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Offline omid

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My question is explain negative feedback in homeostasis using example in the human body?
I am considering using the link below;
if you can please check and tell me if i am on the right track
http://science.jrank.org/pages/3365/Homeostasis.html
please help me out My tutor is a big monster hes going to kill me if I did not do it accurately. Even today he was like shouting at me saying that he needs it by the end of this week.

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Offline Variola

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That link is fine for explaining the basics, but it depends on how much depth your tutor wants you to go into?
If its just a short question then it should be fine, if its longer you might want to use more specific examples of negative feedback loops, glucose metabolism is problably the easiest one to use, or you could use the blood pressure one in the link but that canget a bit more complicated as parts of it can involve pH levels.

EDIT:

http://bcs.whfreeman.com/thelifewire/content/chp50/5002002.html

Thats got a nice animation on it to play with and is well explained.
« Last Edit: 03/06/2009 10:00:09 by Variola »
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Chemistry4me

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Haha, I didn't even see omid's last post.

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Offline Variola

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Haha, I didn't even see omid's last post.

I have a biology radar.... anything biology related blips up on  my screen..[:)]
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Chemistry4me

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Yeah? Can you help me with RNA transcription? Or is that DNA? [:)]

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Offline Chemistry4me

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Argh! Please turn your biology radar to full throttle because mine's broken.

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Offline Variola

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Yeah? Can you help me with RNA transcription? Or is that DNA? [:)]

Its kind of a bit of both!!!! What would you like to know??
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Variola

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Argh! Please turn your biology radar to full throttle because mine's broken.

Only if you sit my Chem Tech exam for me!!!
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Chemistry4me

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What's an Okazaki Ozaki fragment?

-----

And if you can't be bothered answering I don't care. I don't have a biology exam coming up.  [:)]

-----

But if you do, let me know. [:)]
« Last Edit: 03/06/2009 10:48:22 by Chemistry4me »

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Offline Chemistry4me

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Um, your post disappeared. If that isn't stating the obvious.

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Offline Variola

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Lol im doing my genetics work at the moment :)

Ok briefly, DNA has to be synthesized from 5' to 3' direction. Thats fine for the leading strang, but the complimentary lagging strand runs in the opposite 3' to 5' direction. The polymerase can't run continously in that direction.So its made in chunks, called Ozaki fragments, that are 'stitched' together with DNA ligase.

I've got a video on my youtube favorites which is quite good for explaining it.

http://www.youtube.com/watch?v=teV62zrm2P0

 [:)]

  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Variola

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Um, your post disappeared. If that isn't stating the obvious.

Thats because the Tesco man called with my shopping and interrupted me....I closed my laptop down and it posted it without me finishing what I was typing!!
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Chemistry4me

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It's Okazaki! So that's why I couldn't find it on Google! Duh! [:D]
Thanks for the video.

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Offline Variola

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Just realised I made the same spelling mistake in my post... lol it's catching!!
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline Chemistry4me

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You could almost say it's spreading as fast as the swine flu.
Ah, I'm going loony. Time for bed.

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Offline omid

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my monster tutor wants some accurate information because its going to be my last chance of submitting the draft.
so are you sure that the the link i m thinking of using is fine because he has confused me so much that i can not decide what to write and what to leave.

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Offline Variola

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my monster tutor wants some accurate information because its going to be my last chance of submitting the draft.
so are you sure that the the link i m thinking of using is fine because he has confused me so much that i can not decide what to write and what to leave.

Well the information in is is accurate but it isn't explained that well.If it is confusing you, then definatley look for some different links, there are better ones than that.

If I had to answer the question, I would structure is as this

-Give a brief outline of what homeostasis is, and how the body uses homeostatic mechanisms to regulate itsef. Mention that for homeostasis to work you need a receptor, a control center, and an effector. Receptor to sense the change in homeostasis,an effector to do something about the change, a control centre to manage the signals coming in from the receptor and the effector.

-Go into greater detail about one specific negative feedback loop. If you type something into google, like glucose metabolism, blood pressure controls or the menstrual cycle, they are all negative feedback loops. Note down ( or draw) how they work, then put it into the essay. I prefer glucose metabolism as its the easiest to understand ( for me) but you might prefer to do something different. Sometimses just drawing out the diagram for yourself can make it easier to understand

The word negative is a bit misleading, as it seems to imply something is always decreasing. Balances of various hormones do decrease but then others are raised in conjunction with it, so when one level goes down, it is sensed and another level of something is increased.
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob

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Offline omid

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Offline Variola

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how about the link below;
http://www.biology-online.org/4/3_blood_sugar.htm

Thats ok but it doesn't go into that much detail, you might need to put a bit more detail in to satisfy your tutor.
Google the hormone names etc to get some more detail.
  A potty-mouthed, impertinent female who thinks she is God's gift to men" -JimBob