A certain lipid sample consists of a wax of unknown molecular weight and composition. It is known, however that the 2 groups are the same fatty acids. In order to investigate this, saponification and iodine numbers were used. A 3.000 g wax sample was placed under reflux with 20.00 mL of 0.7000 M KOH (56.1056 mg/mmol). It was then back-titrated using a 0.3500 M HCl titrant that required 23.91 mL to the phenolphthalein endpoint. To further characterize this, a 0.100 g sample was titrated for its iodine number. This consumed 3.50 mL of 0.100 N thiosulfate titrant. (Iodine: 126.905 g/eq) a) What is the saponification number of this wax sample? b) What is its Iodine number? c) How would you describe this in terms of unsaturation?

Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
icon
Related questions
Question
A certain lipid sample consists of a wax of unknown molecular weight and composition. It is known, however,
that the 2 groups are the same fatty acids. In order to investigate this, saponification and iodine numbers were
used.
A 3.000 g wax sample was placed under reflux with 20.00 mL of 0.7000 M KOH (56.1056 mg/mmol). It was
then back-titrated using a 0.3500 M HCl titrant that required 23.91 mL to the phenolphthalein endpoint.
To further characterize this, a 0.100 g sample was titrated for its iodine number. This consumed 3.50 mL of
0.100 N thiosulfate titrant. (Iodine: 126.905 g/eq)
a) What is the saponification number of this wax sample?
b)
What is its Iodine number?
c) How would you describe this in terms of unsaturation?
d) Given that it is a wax, what is the general structure of this lipid?
e)
What will be the MW factor for this lipid?
f) What is the average MW of the lipid?
g)
Given the table of molecular weights below, what is the possible identity of the wax?
Compound
MW (g/mol)
Stearic acid (18:0)
284.48
Octadecane (18:0)
254.51
Oleic Acid (18:1)
282.47
9-octadecene (18:1)
252.49
Linoleic Acid (18:2)
280.45
6,9-octadeca-diene (18:2)
250.47
a-Linoleic acid (18:3)
278.44
3,6,9-octadeca-triene (18:3)
248.45
Transcribed Image Text:A certain lipid sample consists of a wax of unknown molecular weight and composition. It is known, however, that the 2 groups are the same fatty acids. In order to investigate this, saponification and iodine numbers were used. A 3.000 g wax sample was placed under reflux with 20.00 mL of 0.7000 M KOH (56.1056 mg/mmol). It was then back-titrated using a 0.3500 M HCl titrant that required 23.91 mL to the phenolphthalein endpoint. To further characterize this, a 0.100 g sample was titrated for its iodine number. This consumed 3.50 mL of 0.100 N thiosulfate titrant. (Iodine: 126.905 g/eq) a) What is the saponification number of this wax sample? b) What is its Iodine number? c) How would you describe this in terms of unsaturation? d) Given that it is a wax, what is the general structure of this lipid? e) What will be the MW factor for this lipid? f) What is the average MW of the lipid? g) Given the table of molecular weights below, what is the possible identity of the wax? Compound MW (g/mol) Stearic acid (18:0) 284.48 Octadecane (18:0) 254.51 Oleic Acid (18:1) 282.47 9-octadecene (18:1) 252.49 Linoleic Acid (18:2) 280.45 6,9-octadeca-diene (18:2) 250.47 a-Linoleic acid (18:3) 278.44 3,6,9-octadeca-triene (18:3) 248.45
Expert Solution
steps

Step by step

Solved in 8 steps

Blurred answer
Knowledge Booster
Basics of Titrimetric Analysis
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
Chemistry
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY