A condensed structural formula is same as a structural formula? Shud i draw all H.???

lillaila · 13 Oct 2003, 1:09 AM

You can hide this advertisement by registering.

This is soooo confusing. Some textbooks use structural formulas as eg. CH3-CH2-CH2branchblahblah-CH3
But other books draw alllllllll hydrogens.
Another book said this first one is still a structural formula but "condensed" ......it still shows adequate info (old conq. chem i think).
?????????????????????????????????

**jm1234567890** · 13 Oct 2003, 9:39 AM

it is same.

no way they expect you to draw 14 carbons.....

+:: $i[Q]u3 ::+ · 13 Oct 2003, 11:44 AM

they won't ask for 14 carbons
i usually draw it like a pic.. with branches and all the hydrogens attached - it makes more sens to me than all this CH3CH2Ch2CH3 nonsense.. well not nonsense.. but u get the drift.

Dangar · 13 Oct 2003, 10:14 PM

yeah i think the CH2CH3CH2 way is a 'condensed' structural formula, but in an exam situation they're not going to ask for a huge molecule so i just do both ways. I usually need to draw the one with all the sticks first to see it properly and then just write the 'condensed' way underneath it. That way you're covered

Rancid Monkey · 14 Oct 2003, 3:47 PM

'condensed structural formula' is CH3CH2CH3

'expanded structural formula' is
H H H
| | |
H - C - C - C - H
| | |
H H H

they *should* specify, but if they dont, be safe and do both. its not like it takes that much longer, and if they didnt say, they cant mark you wrong. most of the time if they ask you to give a formula for something they are looking for the bonds anyway.

and make sure you put H's at the end of all the bonds and dont forget the bond between the O and H in an O-H group. i have seen some teachers forget/tell students not to bother - BAD idea

Rancid Monkey · 14 Oct 2003, 3:49 PM

wtf....not meant to look like that, i swear i put spaces in there.....anyway, you get the point

~*HSC 4 life*~ · 24 Oct 2003, 11:05 PM

still....good effort on that diagram!

Inhuman · 25 Oct 2003, 5:19 PM

My teacher tells us NEVER do the condensed formula; if they ask for a structural formula they mean the diagram

13 Oct 2003, 1:09 AM	#1 (permalink)
lillaila clear as ice HSC: 2003 Gender: Female Location: muahahhahaha Join Date: Feb 2003 Posts: 421 Last Activity: 14 Apr 2005, 10:52 PM	A condensed structural formula is same as a structural formula? Shud i draw all H.??? You can hide this advertisement by registering. This is soooo confusing. Some textbooks use structural formulas as eg. CH3-CH2-CH2branchblahblah-CH3 But other books draw alllllllll hydrogens. Another book said this first one is still a structural formula but "condensed" ......it still shows adequate info (old conq. chem i think). ????????????????????????????????? __________________ It's not what you have but how you feel about it. class of '03

13 Oct 2003, 9:39 AM	#2 (permalink)
jm1234567890 Moderator HSC: 2003 Gender: Male Location: Stanford, CA Join Date: Aug 2002 Posts: 6,405 Last Activity: 10 Sep 2009, 5:37 PM	it is same. no way they expect you to draw 14 carbons..... __________________ Telecommunications Engineering/Maths @ UOW [University Medal] Project "Rate Compatible Protograph Codes" @ UNSW MSc/PhD Electrical Engineering @ Stanford University Flickr

14 Oct 2003, 3:47 PM	#5 (permalink)
Rancid Monkey The other white meat Location: Northbridge, Sydney Join Date: Oct 2003 Posts: 14 Last Activity: 12 Jun 2004, 3:13 PM	'condensed structural formula' is CH3CH2CH3 'expanded structural formula' is H H H \| \| \| H - C - C - C - H \| \| \| H H H they should specify, but if they dont, be safe and do both. its not like it takes that much longer, and if they didnt say, they cant mark you wrong. most of the time if they ask you to give a formula for something they are looking for the bonds anyway. and make sure you put H's at the end of all the bonds and dont forget the bond between the O and H in an O-H group. i have seen some teachers forget/tell students not to bother - BAD idea __________________ Reality is an illusion created by a lack of alcohol

14 Oct 2003, 3:49 PM	#6 (permalink)
Rancid Monkey The other white meat Location: Northbridge, Sydney Join Date: Oct 2003 Posts: 14 Last Activity: 12 Jun 2004, 3:13 PM	wtf....not meant to look like that, i swear i put spaces in there.....anyway, you get the point __________________ Reality is an illusion created by a lack of alcohol

25 Oct 2003, 5:19 PM	#8 (permalink)
Inhuman Member HSC: 2003 Gender: Female Location: In the CSE labs at unsw Join Date: Oct 2003 Posts: 132 Last Activity: 30 Jun 2006, 11:44 PM	My teacher tells us NEVER do the condensed formula; if they ask for a structural formula they mean the diagram __________________ 2nd yr seng/arts @ unsw "No matter how fast light travels it always finds the darkness has gotten there first and is waiting for it" - Terry Pratchett

13 Oct 2003, 11:44 AM	#3 (permalink)
+:: $i[Q]u3 ::+ Jaded Member HSC: 2003 Gender: Female Join Date: Apr 2003 Posts: 901 Last Activity: 30 Jun 2009, 11:42 AM	they won't ask for 14 carbons i usually draw it like a pic.. with branches and all the hydrogens attached - it makes more sens to me than all this CH3CH2Ch2CH3 nonsense.. well not nonsense.. but u get the drift.

13 Oct 2003, 10:14 PM	#4 (permalink)
Dangar Member Location: Sydney Join Date: Apr 2003 Posts: 125 Last Activity: 1 Feb 2004, 1:58 PM	yeah i think the CH2CH3CH2 way is a 'condensed' structural formula, but in an exam situation they're not going to ask for a huge molecule so i just do both ways. I usually need to draw the one with all the sticks first to see it properly and then just write the 'condensed' way underneath it. That way you're covered

24 Oct 2003, 11:05 PM	#7 (permalink)
~HSC 4 life~ Ancient Orator HSC: N/A Gender: Undisclosed Join Date: Aug 2003 Posts: 2,762 Last Activity: 14 Jun 2009, 2:09 PM	still....good effort on that diagram!

Thread Tools
Show Printable Version Email this Page
Rate This Thread
Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
structural name	lanvins	Production of Materials	3	26 Mar 2008 10:23 PM
free programs/software to draw structural diagrams of polymers	karnage	Chemistry	1	15 Mar 2008 4:26 PM
Condensed structural formulae	~ ReNcH ~	Chemistry	6	3 Jul 2005 8:34 PM
Structural formula of citric acid	~ ReNcH ~	Chemistry	4	11 Apr 2005 9:43 PM