Homework Help: science(chem)

Posted by ~christina~ on Friday, March 28, 2008 at 5:30pm.

What would cause the peaks in a IR analysis to be smaller than they should be? My sample had the right peaks where they should be and they were the right shape but were shorter then they should be.

Something different is what the y axis says on the IR analysis that they gave us so we would know how the IR was supposed to look for our samples. But the y axis on the one they gave us said "percent transmittance" while the IR graph had "percent reflectance". Not sure if it's the same.

If they are though then an example of the difference in peak size is:

my sample of 4-bromo-2-chloroacetaniilide
1 middle sized peak: 3275.24 cm-1
and the intensity was : 69.608 % reflectance

The given IR card showed the peak going all the way down to about 30% percent transmitance ( I don't have the exact value)

Thank you.

science(chem) - ~christina~, Friday, March 28, 2008 at 5:32pm
Something different is what the y axis says on the IR analysis that they gave us so we would know how the IR was supposed to look for our samples. But the y axis on the one they gave us said "percent transmittance" while the IR graph Ihad "percent reflectance". Not sure if it's the same.
science(chem) - DrBob222, Friday, March 28, 2008 at 8:47pm
The only explanation I might offer is that you may have performed an ATR (attenuated total reflectance) but I haven't had experience with that instrument. .
science(chem) - ~christina~, Friday, March 28, 2008 at 8:59pm
Oh..yes I did perform an ATR. I didn't think it was that different from a normal IR but I guess it is from what your saying.
science(chem) - ~christina~, Friday, March 28, 2008 at 9:02pm
Thank you Dr.Bob
- science(chem) - DrBob222, Friday, March 28, 2008 at 10:25pm
  I don't know that it's different. I've not used one.
  - science(chem) - ~christina~, Friday, March 28, 2008 at 10:38pm
    Well, you don't need solvent and you just use the sample as is.

Answer this Question

Related Questions

Science - I have my carbon NMR spectra and my product should not have any N in ...
Organic chem lab - Gas Chromatography Graph analysis -- How can I find the peak ...
Org. Chem. - Draw a mechanism that explains how the nitro-substituted aromatic ...
Physical Science - I need help with a few of these questions: 1.Which of the ...
organic chemistry - Write a complete mechanism. Explain each step. Explain the ...
Science - Peaks are not as sharp on the Appalachian Mountains as they are on the...
NMR Organic Chemistry multiple choice - Why do we only see four peaks in the 1H ...
organic chemistry II lab NMR - Why do we only see four peaks in the 1H NMR when ...
organic chemistry - How can looking at traces of GC (looking at their peaks and ...
organic chemistry - How can looking at traces of GC (looking at their peaks and ...

For Further Reading

First Name:
School Subject:
Answer: