Forensic Chemistry
3rd Edition
ST
UV
SOLUTIONS
IA
_A
MANUAL
PP
RO
Suzanne Bell
────────────────────────────────────────────────────
VE
Comprehensive Solutions Manual for
Instructors and Students
D?
© Suzanne Bell. All rights reserved. Reproduction or distribution without permission is
?
prohibited.
© DreamsHub
, Solutions Manual for Forensic Chemistry (3rd Edition)
Suzanne Bell
CRC Press
ST
SECTION 1: METROLOGY AND MEASUREMENT
1. Making Good Measurements
2. Assuring Good Measurements
UV
SECTION 2: CHEMICAL FOUNDATIONS
3. Chemical Fundamentals: Partitioning, Equilibria, and Acid-Base
Chemistry
4. Chromatography and Mass Spectrometry
5. Spectroscopy
IA
SECTION 3: DRUGS AND POISONS
6. Overview of Drug Analysis
_A
7. Novel Psychoactive Substances
8. Fundamentals of Toxicology
9. Applications of Forensic Toxicology
SECTION 4: COMBUSTION EVIDENCE
PP
10. Overview of Combustion Chemistry
11. Fire Investigation and Fire Debris Analysis
12. Explosives
13. Firearms and Firearms Discharge Residue
RO
14. Forensic Chemistry and Trace Evidence Analysis
VE
D?
?
© DreamsHub
, Solutions Manual for Forensic Chemistry, 3e
by Suzanne Bell (All Chapters)
Solutions Manual for End of Chapter Questions
ST
Forensic Chemistry, 3rd edition
UV
Chapter 1
1. A standard of Pb2+ for a gunshot residue analysis using atomic absorption is prepared by first
IA
dissolving 1.0390 g dried Pb(NO3)2 in distilled water containing 1% nitric acid. The solution is
brought to volume in a class A 500.00-mL volumetric flask with an uncertainty of ±0.20 mL.
_A
The solution is then diluted 1:10 by taking 10.00 mL (via an Eppendorf pipet, tolerance ±1.3 μL)
and diluting this in 1% nitric acid to a final volume of 100.00 mL in a volumetric flask with a
tolerance of ±0.08 mL. The balance has an uncertainty of ±0.0002 g.
PP
An unusual feature of this question is that the molecular weight of Pb is listed as 207.2 g/mole
which must be considered in rounding. This point is made in the text as well.
RO
a. Using conventional rounding rules, calculate the concentration of the final solution of Pb2+, in
ppm.
The calculations should be done together, and the results rounded at the end. The only exception
VE
to this is with the formula weight for the lead nitrate, which is rounded separately as an
addition/subtraction:
Formula weight of Pb(NO3)2 = 207.2 + (2 x 14.01) + (2 x 3 x 16.) = 331.22
D?
Formula weight of Pb(NO3)2 = 207.2 + (2 x 14.00674) + (6 x 15.9994) = 331.2
?
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, To obtain the concentration in ppm (mg/L), the molarity is calculated and then converted to the
final value. Note that the moles of Pb in the sample are equal to the moles of Pb(NO3)2 since
there is a 1:1 mole ratio of lead in lead nitrate:
1.0390g Pb ( NO3 )2 1 mole Pb g 1000 mg
207.2 Pb
Pb ( NO3 )2 1 mole Pb ( NO3 )2
g mole g
331.2
ST
mole
0.5000 L
molarity (moles/L) → ppm (mg/L)
UV
= 1300.0 ppm
This solution is diluted by a factor of 1:10 (10.00 mL to 100.00 mL) to yield the final solution
concentration of 130.0 ppm.
IA
The result is rounded to four significant figures, the least number present in any of the measured
values.
_A
b. Determine the absolute and relative uncertainties of each value obtained in part a.
Units must match so convert ul to mL
PP
0.20mL
Large vol flask: = 4.00x10-4
500.00mL
0.08mL
Small vol flask: = 8.00x10-4
100.00mL
RO
0.0002g
Balance: = 1.92 x10-4
1.0390g
1 mL 0.0013mL
Eppendorf: 1.3ul = = 1.30x10 −4
1000uL 10.00mL
VE
c. Report the results as a range by the propagation-of-error method.
This is best done as one calculation to avoid rounding errors:
D?
Uncertainty = ( uncert.balance ) + ( 500mL flask ) + ( Eppendorf ) + (100ml flask )
2 2 2 2
?
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3rd Edition
ST
UV
SOLUTIONS
IA
_A
MANUAL
PP
RO
Suzanne Bell
────────────────────────────────────────────────────
VE
Comprehensive Solutions Manual for
Instructors and Students
D?
© Suzanne Bell. All rights reserved. Reproduction or distribution without permission is
?
prohibited.
© DreamsHub
, Solutions Manual for Forensic Chemistry (3rd Edition)
Suzanne Bell
CRC Press
ST
SECTION 1: METROLOGY AND MEASUREMENT
1. Making Good Measurements
2. Assuring Good Measurements
UV
SECTION 2: CHEMICAL FOUNDATIONS
3. Chemical Fundamentals: Partitioning, Equilibria, and Acid-Base
Chemistry
4. Chromatography and Mass Spectrometry
5. Spectroscopy
IA
SECTION 3: DRUGS AND POISONS
6. Overview of Drug Analysis
_A
7. Novel Psychoactive Substances
8. Fundamentals of Toxicology
9. Applications of Forensic Toxicology
SECTION 4: COMBUSTION EVIDENCE
PP
10. Overview of Combustion Chemistry
11. Fire Investigation and Fire Debris Analysis
12. Explosives
13. Firearms and Firearms Discharge Residue
RO
14. Forensic Chemistry and Trace Evidence Analysis
VE
D?
?
© DreamsHub
, Solutions Manual for Forensic Chemistry, 3e
by Suzanne Bell (All Chapters)
Solutions Manual for End of Chapter Questions
ST
Forensic Chemistry, 3rd edition
UV
Chapter 1
1. A standard of Pb2+ for a gunshot residue analysis using atomic absorption is prepared by first
IA
dissolving 1.0390 g dried Pb(NO3)2 in distilled water containing 1% nitric acid. The solution is
brought to volume in a class A 500.00-mL volumetric flask with an uncertainty of ±0.20 mL.
_A
The solution is then diluted 1:10 by taking 10.00 mL (via an Eppendorf pipet, tolerance ±1.3 μL)
and diluting this in 1% nitric acid to a final volume of 100.00 mL in a volumetric flask with a
tolerance of ±0.08 mL. The balance has an uncertainty of ±0.0002 g.
PP
An unusual feature of this question is that the molecular weight of Pb is listed as 207.2 g/mole
which must be considered in rounding. This point is made in the text as well.
RO
a. Using conventional rounding rules, calculate the concentration of the final solution of Pb2+, in
ppm.
The calculations should be done together, and the results rounded at the end. The only exception
VE
to this is with the formula weight for the lead nitrate, which is rounded separately as an
addition/subtraction:
Formula weight of Pb(NO3)2 = 207.2 + (2 x 14.01) + (2 x 3 x 16.) = 331.22
D?
Formula weight of Pb(NO3)2 = 207.2 + (2 x 14.00674) + (6 x 15.9994) = 331.2
?
Downloaded by: tutorsection | Want to earn $1.236
Distribution of this document is illegal extra per year?
, To obtain the concentration in ppm (mg/L), the molarity is calculated and then converted to the
final value. Note that the moles of Pb in the sample are equal to the moles of Pb(NO3)2 since
there is a 1:1 mole ratio of lead in lead nitrate:
1.0390g Pb ( NO3 )2 1 mole Pb g 1000 mg
207.2 Pb
Pb ( NO3 )2 1 mole Pb ( NO3 )2
g mole g
331.2
ST
mole
0.5000 L
molarity (moles/L) → ppm (mg/L)
UV
= 1300.0 ppm
This solution is diluted by a factor of 1:10 (10.00 mL to 100.00 mL) to yield the final solution
concentration of 130.0 ppm.
IA
The result is rounded to four significant figures, the least number present in any of the measured
values.
_A
b. Determine the absolute and relative uncertainties of each value obtained in part a.
Units must match so convert ul to mL
PP
0.20mL
Large vol flask: = 4.00x10-4
500.00mL
0.08mL
Small vol flask: = 8.00x10-4
100.00mL
RO
0.0002g
Balance: = 1.92 x10-4
1.0390g
1 mL 0.0013mL
Eppendorf: 1.3ul = = 1.30x10 −4
1000uL 10.00mL
VE
c. Report the results as a range by the propagation-of-error method.
This is best done as one calculation to avoid rounding errors:
D?
Uncertainty = ( uncert.balance ) + ( 500mL flask ) + ( Eppendorf ) + (100ml flask )
2 2 2 2
?
Downloaded by: tutorsection | Want to earn $1.236
Distribution of this document is illegal extra per year?
