Chemical Forums

Please login or register.

Login with username, password and session length

Sponsored links

Pages: [1]   Go Down

Author Topic: 18 different isomers of octane (c8h18)  (Read 84923 times)

0 Members and 1 Guest are viewing this topic.

patrisha_boo

  • Guest
18 different isomers of octane (c8h18)
« on: March 29, 2005, 06:29:30 PM »

1)
   h h h h h h h h
h-c-c-c-c-c-c-c-c-h
   h h h h h h h h

2)
   h h h h h h   h    h
h-c-c-c-c-c-c -  c-    c-h
  h h h h h h   h  h-c-h
                           h
3)
   h h h h h h
h-c-c-c-c-c-c-h
   h h h h hch-hch
                h    h
4)
   h h h h h  
h-c-c-c-c-c-h
   h h hch hch-hch
          h    h    h
5)
   h    h    h    h
h-c-   c-   c-    c  -h
  hch hch hch hch
    h    h    h    h

I don't really know how to find the other 13 isomers.
Logged

AWK

  • Global Moderator
  • Sr. Member
  • ***
  • Mole Snacks: +358/-108
  • Offline Offline
  • Gender: Male
  • Posts: 4860
Re:18 different isomers of octane (c8h18)
« Reply #1 on: March 29, 2005, 10:17:32 PM »

It should be 18. Try to name all these isomers.
« Last Edit: March 30, 2005, 02:04:07 AM by AWK »
Logged
AWK

Octane

  • Guest
Re:18 different isomers of octane (c8h18)
« Reply #2 on: May 19, 2005, 02:41:41 PM »

n-octane

2-methylheptane
 3-methylheptane
4-methylheptane

2,2-dimethylhexane
2,3-dimethylhexane
2,4-dimethylhexane
2,5-dimethylhexane
3,3-dimethylhexane
3,4-dimethylhexane
3-ethylhexane

2,2,3-trimethylpentane
2,2,4-trimethylpentane
2,3,3-trimethylpentane
2,3,4-trimethylpentane
3-ethyl-2-methylpentane
3-ehtyl-3-methylpentane
 
2,2,3,3-tetramethylbutane

I belive that that is all, I have rechecked them several times and no doubling, there is 18 of them too.
Logged

Donaldson Tan

  • Editor, New Asia Republic
  • Retired Staff
  • Sr. Member
  • *
  • Mole Snacks: +260/-11
  • Offline Offline
  • Gender: Male
  • Posts: 3177
    • New Asia Republic
Re:18 different isomers of octane (c8h18)
« Reply #3 on: May 19, 2005, 06:24:49 PM »

gosh.. 900++ views for this post.. LOL
Logged
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

Communique

  • Guest
Re:18 different isomers of octane (c8h18)
« Reply #4 on: May 28, 2005, 07:11:44 AM »

2,3,4-trimethylpentane
3-ethyl-2-methylpentane
3-ehtyl-3-methylpentane

Wouldnt it be
3,3,4-trimethylpentane
2-methyl-3-ethylpentane
3-methyl-3-ethylpentane

The last two I think are the same as what you have posted, just named a little differently. As a lab in chem class were supposed to name and draw out all the isomers of octane and my question is, would a difference in naming like that matter at all? Because they are really the same thing I think...
Logged

janne18

  • Guest
Re:18 different isomers of octane (c8h18)
« Reply #5 on: May 28, 2005, 11:31:53 PM »

Wouldnt it be
3,3,4-trimethylpentane
2-methyl-3-ethylpentane
3-methyl-3-ethylpentane

The last two I think are the same as what you have posted, just named a little differently. As a lab in chem class were supposed to name and draw out all the isomers of octane and my question is, would a difference in naming like that matter at all? Because they are really the same thing I think...

Nope. I agree with Octane. Remember that substituents are supposed to have the lowest possible numbers and that the substituents should be in alfabetic order. ethyl before methyl :)
Logged

AWK

  • Global Moderator
  • Sr. Member
  • ***
  • Mole Snacks: +358/-108
  • Offline Offline
  • Gender: Male
  • Posts: 4860
Re:18 different isomers of octane (c8h18)
« Reply #6 on: May 29, 2005, 07:34:46 PM »

Octane did some errors.
the proper name of all isomers are (left to right, up to down  - see my scheme):
n-octane,  2-methylheptane, 3-..., 4-...,
2,2-dimethylhexane, 2,3-..., 2,4-..., 2,5-...,
3,3-dimethylhexane, 3,4-..., 3-ethylhexane,
2,2,3-trimethylpentane, 2,2,4-..., 2,3,3-..., 2,3,4-...,  3-ethyl-2-methylpentane,
3-ethyl-3-methylpentane,
2,2,3,3,-tetramethylbutane.
Logged
AWK

woelen

  • Chemist
  • Full Member
  • *
  • Mole Snacks: +36/-2
  • Offline Offline
  • Gender: Male
  • Posts: 277
  • The art of wondering makes life worth living...
    • Science made alive
Re:18 different isomers of octane (c8h18)
« Reply #7 on: May 29, 2005, 09:45:26 PM »

It should be 18. Try to name all these isomers.
Wow... you did your homework very well.

Just to tease you with this puzzle on alkanes.... ;D
What is the generic mathematical expression of the number of isomers of CnH2n+2?
Give the number of isomers as an integer function of n.

Below follows the value of this function for some small values of n.

1 1
2 1
3 1
4 2
5 3
6 5
7 9
8 18
9 35
10 75
12 355
15 4347



Wilco
Logged
Want to wonder? See http://www.oelen.net/science

AWK

  • Global Moderator
  • Sr. Member
  • ***
  • Mole Snacks: +358/-108
  • Offline Offline
  • Gender: Male
  • Posts: 4860
Logged
AWK
Pages: [1]   Go Up
 

Mitch Andre Garcia's Chemical Forums 2003-Present.

Page created in 0.116 seconds with 23 queries.