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Tutorial 2 CHM260

This document is a tutorial for CHM 260 Basic Instrumental Analysis, focusing on molecular absorption spectroscopy. It includes questions on components of spectroscopic instruments, requirements for IR activity, analysis of IR spectra for various compounds, and sample preparation methods. The tutorial aims to assess students' understanding of the theory, instrumentation, and applications of molecular absorption spectroscopy.

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Teratak Biru
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10 views4 pages

Tutorial 2 CHM260

This document is a tutorial for CHM 260 Basic Instrumental Analysis, focusing on molecular absorption spectroscopy. It includes questions on components of spectroscopic instruments, requirements for IR activity, analysis of IR spectra for various compounds, and sample preparation methods. The tutorial aims to assess students' understanding of the theory, instrumentation, and applications of molecular absorption spectroscopy.

Uploaded by

Teratak Biru
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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ACADEMIC SESSION 2016/2017 SESSION 1: JUN – OCTOBER 2016

CHM 260 BASIC INSTRUMENTAL ANALYSIS


TUTORIAL 2: MOLECULAR ABSORPTION SPECTROSCOPY: THEORY,
PAHANG BRANCH INSTRUMENTATION AND APPLICATION [Type text]

Name: Student No:

Answer the following questions.

1) Provide any one (1) example of the following components found in spectroscopic instruments.
i) A continuum source for visible region
ii) A thermal detector.
iii) A cell material for IR analysis.

2) What are the requirements for an organic molecule to be IR active?

3) The following is the IR spectrum for ethyl acetate, C4H8O2.

Identify two (2) significant peaks and give the wavenumber and bonds that are consistent with the
molecule.

S.N. Jaafar 1
ACADEMIC SESSION 2016/2017 SESSION 1: JUN – OCTOBER 2016
CHM 260 BASIC INSTRUMENTAL ANALYSIS
TUTORIAL 2: MOLECULAR ABSORPTION SPECTROSCOPY: THEORY,
PAHANG BRANCH INSTRUMENTATION AND APPLICATION [Type text]
4) Figure below shows the IR spectrum of propanoic acid.

Provide two (2) most obvious absorption bands and approximate wave number for the spectrum.

5) Given below is the FTIR spectrum of 3-hydroxy benzaldehyde.

%
Tra
ns
mi
tta
nce

Wavenumber / cm-1

Select three (3) important peaks and determine the functional groups and wavenumbers
associated with the peaks.

S.N. Jaafar 2
ACADEMIC SESSION 2016/2017 SESSION 1: JUN – OCTOBER 2016
CHM 260 BASIC INSTRUMENTAL ANALYSIS
TUTORIAL 2: MOLECULAR ABSORPTION SPECTROSCOPY: THEORY,
PAHANG BRANCH INSTRUMENTATION AND APPLICATION [Type text]
6) The following questions refer to IR spectroscopy.

i) Describe the sample preparation of a solid compound using the mull method.

ii) Explain briefly why homonuclear molecules such as O2, N2 and Cl2 do not absorb

infrared (IR) radiation.

7) Bottle of isomeric compounds, acetone and allyl alcohol, were incorrectly labeled. Use the
following IR information to help you determine which compound is in which bottle.

Bottle no. IR absorption peaks, cm-1 Compound


1 3333 (broad), 1030 (medium) ?
2 1710 (sharp) ?

8) Analyze the following IR spectrum of an ester, methyl propanoate, CH3CH2COOCH3.

%
Tra
ns
mi
tta
nce

Wavenumber / cm-1

Select the two (2) most significant peaks associated with the ester from the given spectrum and
provide the bonds associated with each peak.

S.N. Jaafar 3
ACADEMIC SESSION 2016/2017 SESSION 1: JUN – OCTOBER 2016
CHM 260 BASIC INSTRUMENTAL ANALYSIS
TUTORIAL 2: MOLECULAR ABSORPTION SPECTROSCOPY: THEORY,
PAHANG BRANCH INSTRUMENTATION AND APPLICATION [Type text]

S.N. Jaafar 4

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