Principles of Instrumental Analysis
Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 17, Problem 17.1QAP

Cyclohexnone exhibits its strongest IR absorption hand at 5.86 μ m, and at this wavelength there is a linear relationship between absorbance and concentration.
(a) Identify the part of the molecule responsible for the absorbance at this wavelength.
(b) Suggest a solvent that would be suitable for a quantitative analysis of cyclohexanone at this wavelength.
(c) A solution of cyclohexanone (4.0 mg/mL) in the solvent selected in part (b) exhibits a blank-corrected absorbance of 0.800 in a cell with a path length of 0.025 mm. What is the detection limit for this compound under these conditions if the noise associated with the spectrum of the solvent is 0.001 absorbance units?

Expert Solution
Check Mark
Interpretation Introduction

(a)

Interpretation:

The part of the molecule that is responsible for absorbance at the given wavelength is to be stated.

Concept introduction:

The IR absorption spectroscopy makes use of a mid infrared light that detects the particular types of chemical bonds in a given sample for the purpose of the identification of organic and organomettalic compounds. In the IR absorption spectra, there are two regions: Functional group region and the fingerprint region.

Answer to Problem 17.1QAP

The part of the molecule that is responsible for absorbance at the given wavelength is Carbonyl ( C=O ).

Explanation of Solution

Given information:

The IR absorption band is 5.86μm.

The expression for the wave number is:

WaveNumber=1λ   ......(I)

Here, the wavelength is λ.

Substitute 5.86μm for λ in Equation (I)

WaveNumber=15.86×106m=(0.1706×106m1)(1m102cm)=1706cm1

1706cm1 is the value responsible for the absorption of the carbonyl group.

Expert Solution
Check Mark
Interpretation Introduction

(b)

Interpretation:

A solvent that would be suitable for quantitative analysis of cyclohexanone at the given wavelength is to be stated.

Concept introduction:

Quantitative analysis refers to the determination of relative or absolute quantity of a substance in a given sample. There are several methods of carrying out the quantitative analysis of the samples. These methods include gravimetric and volumetric analysis.

Answer to Problem 17.1QAP

A solvent that would be suitable for quantitative analysis of cyclohexanone at the given wavelength is cyclohexane and any chlorinated solvent.

Explanation of Solution

The solvent that is suitable for quantitative analysis of cyclohexanone at the given wavelength should be cheap and less toxic in nature.

The solvents that can be used are cyclohexane and any chlorinated solvent.

Expert Solution
Check Mark
Interpretation Introduction

(c)

Interpretation:

The detection limit for the compound is to be stated.

Concept introduction:

The detection limit refers to the smallest quantity of the substance that can be differentiated from the absence of that particular substance with a certain level of confidence.

Answer to Problem 17.1QAP

The detection limit for the compound is 0.005mg/mL.

Explanation of Solution

Given information:

Noise associated with the spectrum of the solvent is 0.001 absorbance units.

The expression for the Beer’s Law,

A=abc   ......(I)

Here, the absorbance is A, the concentration is c and the width of the sample cell is b.

Substitute 0.800 for A and 4.00mg/mL in Equation (I)

0.800=ab(4.00mg/mL)   ......(II)

Substitute 0.001 for A and cmin for c in Equation (I)

0.001=abcmin   ......(III)

Divide Equation (III) by Equation (II)

0.0010.800=cmin4.00mg/mLcmin=4.00mg/mL(0.0010.800)cmin=0.005mg/mL

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Draw the structural formulas of the following compounds and indicate the number of NMR signals that would be expected for each compound. (a) methyl iodide (b) 2,4-dimethylpentane (c) cyclopentane (d) propylene (propene)
(a) Compound A has molecular formula C5H10O. It shows three signals in the 1H-NMR spectrum - a doublet of integral 6 at 1.1 ppm, a singlet of integral 3 at 2.14 ppm, and a quintet of integral 1 at 2.58 ppm. Suggest a structure for A and explain your reasoning. (b) Compound B has molecular formula C8H6O2. The IR, 1H-NMR, and 13C-NMR spectra are shown below, they are also downloadable for closer inspection by clicking the link under the spectral data. Suggest a structure for B and explain your reasoning. (c) Compound C has molecular formula C5H8O. The IR, mass, 1H-NMR, and 13C-NMR spectra are shown below, they are also downloadable for closer inspection by clicking the link under the spectral data. Suggest a structure for C and explain your reasoning.
(a) Compound A has molecular formula C5H10O. It shows three signals in the 1H-NMR spectrum - a doublet of integral 6 at 1.1 ppm, a singlet of integral 3 at 2.14 ppm, and a quintet of integral 1 at 2.58 ppm. Suggest a structure for A and explain your reasoning. (b) Compound B has molecular formula C8H6O2. The IR, 1H-NMR, and 13C-NMR spectra are shown below, they are also downloadable for closer inspection by clicking the link under the spectral data. Suggest a structure for B and explain your reasoning. (c) Compound C has molecular formula C5H8O. The IR, mass, 1H-NMR, and 13C-NMR spectra are shown below, they are also downloadable for closer inspection by clicking the link under the spectral data. Suggest a structure for C and explain your reasoning.
Knowledge Booster
Background pattern image
Chemistry
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781259911156
Author:Raymond Chang Dr., Jason Overby Professor
Publisher:McGraw-Hill Education
Text book image
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning
Text book image
Organic Chemistry
Chemistry
ISBN:9780078021558
Author:Janice Gorzynski Smith Dr.
Publisher:McGraw-Hill Education
Text book image
Chemistry: Principles and Reactions
Chemistry
ISBN:9781305079373
Author:William L. Masterton, Cecile N. Hurley
Publisher:Cengage Learning
Text book image
Elementary Principles of Chemical Processes, Bind...
Chemistry
ISBN:9781118431221
Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:WILEY
IR Spectroscopy; Author: Professor Dave Explains;https://www.youtube.com/watch?v=_TmevMf-Zgs;License: Standard YouTube License, CC-BY