Tutor.com Organic Chemistry Session

Jun. 11, 2013

  • Poor
  • Fair
  • Average
  • Good
  • Excellent
  • Click to rate this Poor
  • Click to rate this Fair
  • Click to rate this Average
  • Click to rate this Good
  • Click to rate this Excellent


Session Transcript - Science - Chemistry, 6/8/2013 5:11PM - Tutor.comSession Date: 6/8/2013 5:11PM
Length: 36.1 minute(s)
Subject: Science - Chemistry


System Message
[00:00:00] *** Please note: All sessions are recorded for quality control. ***

Guest (Customer)
[00:00:01] stereochemistry
[00:00:05] hi

Lance L (Tutor)
[00:00:06] Hi!

Guest (Customer)
[00:00:11] how are you

Lance L (Tutor)
[00:00:18] Great! How are you?

Guest (Customer)
[00:00:50] great
[00:01:01] exept for chem of course

Lance L (Tutor)
[00:01:13] Haha

Guest (Customer)
[00:01:35] i am having alot of trouble with this and i have been at it for a looong time

Lance L (Tutor)
[00:01:52] Well, hopefully I can help

Guest (Customer)
[00:02:10] i hope so
[00:04:10] ok so for these questions i have to tell if these are identical, diastereomers or enantiomers
[00:04:26] my last tutor said they were enatiomers but i dont see it at all

Lance L (Tutor)
[00:04:39] Hmmm.. I'm afraid I can't help with this one
[00:04:49] It's out of my area of expertise, sorry
[00:04:59] Would you like a transfer?

Guest (Customer)
[00:05:15] awww.. sure that would be ok

System Message
[00:06:29] *** The session has been transferred. ***

Guest (Customer)
[00:06:30] hi

Katrina V (Tutor)
[00:06:54] Hi! Welcome to tutor.com !
[00:07:14] My name is Katrina. I see you have started a problem with another tutor already.
[00:07:39] Let me take a look at what you have put in the queue already. Give me one moment as I do this.

Guest (Customer)
[00:07:41] yes... im having alot of trouble with this
[00:07:45] ok

Katrina V (Tutor)
[00:09:24] Ok I think we can figure this out!

Guest (Customer)
[00:09:30] i hope so

Katrina V (Tutor)
[00:10:11] You mentioned a few terms... enantiomers and diasteriomers. What definitions do you have for these, or do you yet?

Guest (Customer)
[00:10:38] yes enantiomers are mirror images that cant be superimposed
[00:11:00] and diastereomers are stereoisomers that are not enatiomers

Katrina V (Tutor)
[00:11:52] Good. Enantiomers have to be mirror images
[00:12:50] the term diastereomers is new to me... but it sounds like they could not be mirror images obviously. Let me research this for you. Do you have a few minutes so I can provide you with correct information?

Guest (Customer)
[00:13:15] sure
[00:13:16]

Katrina V (Tutor)
[00:13:41] Great I'm going to get my organic chemistry book from college out..
[00:13:42] I'm researching...
[00:16:15] Ok I'm back
[00:16:59] So, as we knew...enantiomers are mirror images, and I have confirmed that diastereomers are stereoisomers that are not mirror images
[00:17:48] Are you clear on the definition of stereoisomers?
[00:17:59] just in general?

Guest (Customer)
[00:17:58] yes

Katrina V (Tutor)
[00:18:01] ok good
[00:18:22] So the structures you drew...do you think they are stereoisomers?

Guest (Customer)
[00:18:58] yes

Katrina V (Tutor)
[00:19:04] That's right!
[00:19:11] Now to the confusing part...are they mirror images?

Guest (Customer)
[00:19:35] thats where i get lost

Katrina V (Tutor)
[00:19:53] let me draw a picture...

Guest (Customer)
[00:19:55] ok

Katrina V (Tutor)
[00:20:36] Ok...assume my lines are straight LOL!

Guest (Customer)
[00:20:41] haha ok

Katrina V (Tutor)
[00:20:49] These two objects are mirror images of one another
[00:21:08] Do you see how if we flipped one over, they could be superimposed to be the same shape?
[00:21:38] in your head, flip the one on the right like you are flipping the page of a book...

Guest (Customer)
[00:21:55] ok
[00:21:57] yes

Katrina V (Tutor)
[00:22:03] Also try this...
[00:22:12] put your hands out...palms up
[00:22:27] if you "flip" your right hand over the top of your left hand they would be the same
[00:22:52] they have to be EXACTLY the same to be mirror images, and it must only take 1 flip...not a flip and a turn

Guest (Customer)
[00:22:59] ok

Katrina V (Tutor)
[00:23:35] So let's look at your structures... each methyl group, each chlorine, bromine etc... must match up exactly in ONE flip if they are mirror images
[00:23:58] I'm going to redraw the one on the right...flipped...
[00:26:19] ok... do you see how my image is the one on the right only flipped?

Guest (Customer)
[00:26:50] yea now i see it

Katrina V (Tutor)
[00:27:02] Ok good...now does it match EXACTLY the one on the left?

Guest (Customer)
[00:27:17] well they cant be superimposed

Katrina V (Tutor)
[00:27:24] right, they can't

Guest (Customer)
[00:27:25] must be enatiomers

Katrina V (Tutor)
[00:27:46] remember the definition of enantiomers is that they are mirror images
[00:28:04] they can only be mirror images if they can be flipped once and then superimposed...

Guest (Customer)
[00:28:24] but we fliped it onece
[00:28:27] once

Katrina V (Tutor)
[00:28:40] right...we flipped it once...and it still cant be superimposed
[00:28:54] if it were an enantiomer...once we had flipped it, it would be able to be superimposed
[00:29:22] Does that make sense?

Guest (Customer)
[00:29:48] hmmm

Katrina V (Tutor)
[00:29:50] Remember on our shapes...once we flip that L on the right...it would match ...that's a mirror image

Guest (Customer)
[00:30:06] i was taught that an enatiomer was a mirror image that cant be superimposed

Katrina V (Tutor)
[00:30:15] it cant until you flip it
[00:30:24] I was just showing you that once you flip it it could be
[00:30:32] see our shapes...they can't be superimposed the way that they are
[00:30:36] only once we flip
[00:31:06] So you are right that they can't readily be superimposed.

Guest (Customer)
[00:31:07] our hands are enatiomers right?

Katrina V (Tutor)
[00:31:11] correct!
[00:31:31] if you put your palms up...without flipping one hand over the other, they cant be superimposed
[00:31:40] but when you flip your right hand, they match

Guest (Customer)
[00:32:00] so these arent enatiomers

Katrina V (Tutor)
[00:32:08] right, they are not
[00:32:12] very good!
[00:32:18] This is tricky stuff, don't get discouraged

Guest (Customer)
[00:32:30] those are though right?

Katrina V (Tutor)
[00:32:49] they still aren't quite...
[00:33:09] see how the Br at the bottom of the one on the right would be covering a Cl on the bottom of the one on the left?
[00:33:14] They don't match perfectly

Guest (Customer)
[00:33:31] oh yea

Katrina V (Tutor)
[00:33:41] so everything would need to be perfectly the same

Guest (Customer)
[00:33:46] ok gotcha

Katrina V (Tutor)
[00:33:52] ok wonderful!
[00:34:05] Do you have any questions about anything we went over today?

Guest (Customer)
[00:34:11] so they arent enantiomers they are either identical or diastereomers

Katrina V (Tutor)
[00:34:29] right! So which do you think? Are they identical?

Guest (Customer)
[00:34:47] not the way they are no

Katrina V (Tutor)
[00:34:55] right so that leaves...?

Guest (Customer)
[00:34:59] they must be diastereomers

Katrina V (Tutor)
[00:35:04] You got it!
[00:35:13]

Guest (Customer)
[00:35:20] can we do more?

Katrina V (Tutor)
[00:35:32] Since we have finished this question and there are students waiting, it would be best if you log back on and connect to another tutor to ask your next question.
[00:35:59] It was great working with you!
[00:36:35] Thanks for using Tutor.com. Please fill out the survey as you leave so we can learn how we can better help you in the future! 

Guest (Customer)
[00:36:52] thank you
[00:36:53] bye

Katrina V (Tutor)
[00:37:04] Bye! Have a wonderful afternoon!