Chem 336 - 338 Lab Lecture
C 336-01 Organic Chemistry Laboratory II
and
C 338-01 Organic Chemistry Laboratory II
Honors
Dr. Margareta Séquin
Office: Science 106C;
Office Hours: Tu 11-12 pm, Th 1-2 pm and by appt.
e-mail: msequin @ sfsu.edu
Phone: 415-405-0315
http://userwww.sfsu.edu/~msequin
First half of semester: Syntheses and methods of evaluation
Second half: C336 “Unknowns”. C338 Final Project
http://userwww.sfsu.edu/~msequin
Prerequisites:
C336: passing grade (C or better) in Chem 333, 334; Chem
335 (can be taken concurrently).
C338: B or better.
Prerequisites will be strictly applied.
A student who withdraws from Chem 335 must also
withdraw from Chem 336 or Chem 338.
Text: “Chem 334, 336, and 338 Organic Chemistry
Laboratory”, SFSU 2005, with Mayo, Pike, Trumper,
"Microscale Organic Laboratory", 4th Ed.; Wiley Custom Ed.
Use your lecture text for reference!
Grading
C336 and C338: MiniQuizzes at the end of lab lectures, 2 pts. each
C336 and C338: One Midterm Exam (100 points)
C336: Final Exam (150 pts.)
C338: Special Project Final Report, worth 150 pts.
Lab reports: 20 points/ lab report 1 - 4. Lab reports V and VI will be
combined and will be 30 pts. Unknown reports (C336) will be 30 pts. each.
Lab Notebooks will be checked regularly.
Your total class grade will be calculated as follows:
40% Exams % (Midterm, plus Mini Quizzes, plus Final Exam or Project, %)
30% Lab reports %
30% Lab preparation, notebook, effort, attendance, participation.
Total class grade:
>/=90% A; 85 -<90% A-; 80 -<85% B+; 75 -<80% B; 70 -<75% B-; 65 <70% C+; 60 -<65% C; 55 -<60% C-; 50 -< 55% D+; 45 -<50% D; 40 <45 D-; <40% F
Exp.1: Solvolysis of tert Butyl Chloride
CH 3
CH 3
C Cl
CH 3
CH 3
+ H 2O
CH 3
C OH
+ HCl
CH 3
1. IUPAC name for tert butyl chloride, for the alcohol
product?
2. Why does changing the solvent medium affect the rate?
60%water:40%acetone; 70%water:30%acetone; 80%water:20%acetone
See Helpful Websites and your lecture text and:
http://www.cem.msu.edu/~reusch/VirtualText/alhalrx2.htm#hal5
CH 3
CH 3
C Cl
CH 3
+ H 2O
CH 3
CH 3
C OH
+ HCl
CH 3
Measuring the tenth–life in our reaction
What is a possible by-product of our reaction? Does this
affect our data?
How would a one-third decrease of concentration of RX
affect the reaction rate?
Calculations for Exp.1: Solvolysis of tert Butyl Chloride
CH 3
CH 3
C Cl
CH 3
+ H 2O
CH 3
Reaction Rate =
CH 3
C OH
+ HCl
CH 3
-d(reactant)
=
dt
p.354-355
-d[RCl]
dt
= k[RCl]
Calculations for Exp.1: Solvolysis
1.
-d[RCl]
dt
= k[RCl]
2.
-d[RCl]
[RCl]
= k dt
3.
-
[RCl]
[RCl] o
d[RCl]
[RCl]
4.
t
=
k dt
0
-ln
[RCl]
[RCl] o
= kt
Calculations for Exp.1: Solvolysis
-ln
[RCl]
[RCl] o
= kt
at t10%, [RCl] = 0.90 [RCl]o
0.90[RCl] o
-ln
= kt 10%
[RCl]o
-ln 0.90 = 0.1053 = kt 10%
0.1053
t10%
= k
Units of k?
How could you calculate k by using the half life?
Arrhenius Equation and Calculation of Ea and A
-Ea/RT
k = Ae
R=1.987216 cal/K mol
What does Ea tell us about the reaction?
ln k = ln A -Ea/RT
y= b
+ mx
ln k
Plot ln k vs. 1/T for each
solvent mixture
1/T
Arrhenius Plots
0
0.0032 0.00325 0.0033 0.00335 0.0034 0.00345 0.0035 0.00355
-1
-2
-3
ln (k)
-4
60/40
y = -13082x + 38.64
70/30
80/20
-5
y = -12362x + 35.503
-6
-7
-8
y = -11872x + 32.619
-9
-10
1/T (Kelvin)
Next time:
• Kinetics (conclusion)
• Friedel-Crafts (Exp.2)
• MiniQuiz on today’s class (Exp.1)
Please fill out roll form and hand it in.
Thank you.