CHEM 233 Final Exam Questions and Correct Answers/ Latest Update / Already Graded

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CHEM 233 Final Exam Questions and
Correct Answers/ Latest Update / Already
Graded
Mass spectrometry separates compounds based on what
characteristic?

Ans: mass/charge ratio


Electrospray ionization mass spectroscopy often results in analyte
molecules fragmenting. (T/F)

Ans: F


The fingerprint region is a difficult to interpret area of an IR spectrum
(T/F)

Ans: T


Which of the following types of carbonyl would generally have a
stretch located below 1700 cm-1

Ans: amide (or conjugated carbonyls)


The stretch for a C-H bond where the carbon is sp2 hybridized would
be located where on an IR spectrum?

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Ans: just above 3000 cm-1 (3000-3100)


Electrospray ionization is a soft ionization technique. (T/F)

Ans: T


Which of the following electrospray ionization mass spectra
corresponds to a compound that contains one chlorine atom?

Ans: The one with the 3:1 ratio


Which of the following electrospray ionization mass spectra
corresponds to a compound that contains one bromine atom?

Ans: The one with 2 peaks of the same height


Which of the following electrospray ionization mass spectra
corresponds to a molecule with a neutral molecular weight of 102
g/mol?

Ans: 103 (H+) or 125 (Na+)


A non-polar bond will always show a signal in an IR spectrum. (T/F)

Ans: F - symmetric bonds will not show up



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Increasing the mass of atoms connected by a bond results in the
absorbance of a higher wavenumber of light. (T/F)

Ans: F


Select the bond that would absorb the highest wavenumber of light in
an IR experiment.



C-N single bond



C-N double bond



C-N triple bond



Cannot be determined

Ans: C-N triple bond (triple bonds absorb higher ppm)


Which of the following wavenumber ranges corresponds to the
fingerprint region in an IR spectrum?




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1650-1750 cm-1



2900-3100 cm-1



3200-4000 cm-1



< 1500 cm-1

Ans: < 1500 cm-1


Which of the following structures would you expect to have a carbonyl
stretch above 1700 cm-1 in an IR spectrum? Select all that apply.

Ans: ester and aldehyde


Which of the following IR stretches would be consistent with the C-H
bond in the below structure where the carbon is sp hybridized? (H -
C☰C)



3300 cm-1



3100 cm-1


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