ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Destiny on June 02, 2012, 08:11:10 pm

Title: Questions
Post by: Destiny on June 02, 2012, 08:11:10 pm

Hey guys, could I ask for some help with questions  :-[?

(http://img137.imageshack.us/img137/9900/chemistryquestion.png)
Question 4 (LCATT 2012)
What method would the research chemist most likely have used to identify the hydrocarbons shown above in the gas chromatogram?
A. Mass Spectroscopy
B.  ¹H NMR
C. Infrared Spectroscopy
D. UV- Visible Spectroscopy
I chose B and the answer was A. Any particular reason why it's A and not B...?

Title: Re: Questions
Post by: charmanderp on June 02, 2012, 09:33:28 pm

Because using A you can easily find out the molar mass of each compound. From those hydrocarbons, no two hydrocarbons share the same molar mass and hence they can be distinguished on that basis.

Title: Re: Questions
Post by: sam0001 on June 02, 2012, 09:57:32 pm

Hey what's lcatt? Never heard of that before!

Title: Re: Questions
Post by: Destiny on June 02, 2012, 10:02:51 pm

Ahh, thankyou :D
Sam- Lisachem Analytical topic test. :3

And another question guys, for IR do we say it tells us what bonds are present in the substance, not functional groups?  Because I came across a question that said it detected function groups, but I don't think C-H is a functional group.  Also with the Benzene ring, does it classify as a functional group? teacher said it was a functional group, but an exam said it wasn't o.o