Organic Chemistry Introduction

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CHEM305
Organic Chemistry I
Introduction
Dr. Ralph C. Gatrone
Department of Chemistry and Physics
Virginia State University
Fall, 2009
Fall, 2009
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Objectives
• Discuss syllabus
• Discuss course requirements
• Review general chemistry
Fall, 2009
2
Organic Chemistry I
CHEM305-01-081
• Office Hours
– T: 2:00 – 5:00 and W: 9:00 – 12:00
– by appointment (524-5762)
• Office: HM239Nb
• Email: [email protected]
• I only respond to an email address that
ends in @vsu.edu
Fall, 2009
3
Organic Chemistry 1
Course Description
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Survey of compounds composed of carbon
Nomenclature
Structure
Physical properties
Reactions
Mechanisms
Fall, 2009
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Course Emphasis
• Organic reactions
• Molecular orbital theory
• Organic Mechanisms
• Molecules of biological importance
• Critical thinking skills
• Skills necessary to do well on
• MCAT, PCAT, OAT, DAT, others
Fall, 2009
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Roles
• My role
• Professor
• Guide
• Your Role
• Student
• Understand the material!
Fall, 2009
6
The Teacher versus the Professor
• A teacher conveys information to provide a
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student with certain skills and a knowledge base.
A professor professes the truth about their area
of expertise while providing the student with the
skills to accept or refute that truth.
Ideally the professor imparts a sense of wonder
such that the student will push the limits of our
understanding.
The student develops the necessary skills and
knowledge base to succeed.
Fall, 2009
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Requirements and Prerequisites
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Course Materials
Text: Organic Chemistry A Biological Approach, John McMurry
You must purchase the book.
A study guide is available. It is not required.
• Prerequisites
• CHEM101 or 111, 102 or 112
• Associated Laboratories
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Foundation from General Chemistry
Quantum mechanics
Solution chemistry
Acid Base Chemistry
Kinetics
Thermodynamics
Fall, 2009
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Prerequisites are critical
• You must have passed these courses
• If you have not passed these courses
• You must drop the course immediately
• If not sooner!
Fall, 2009
9
Homework
• Every problem in the Text is recommended.
• However,
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They will not be graded.
They will not be collected.
They will not be discussed in class.
They are available to you to determine if you
understand the material.
– If you choose not to do the problems it is nearly a
guarantee that you will not pass this class.
Fall, 2009
10
Evaluation
• Test 1: Chapters 1 – 6
• Test 2: Chapters 1 – 7
• Test 3: Chapters 1 – 10
• Final Exam Chapters 1 – 10
100pts
100pts
100 pts
200pts
• Total Possible
500pts
Fall, 2009
11
Evaluation – Grade Calculation
• Final Grades will be computed:
– Earned Points
>450
400 – 449
325 – 399
250 – 324
<249
Fall, 2009
Final Grade
A
B
C
D
F
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Extra Credit
• No extra credit will be given.
• If you follow my instructions
• You will not need it.
• If you do not follow these instructions
• It will not help.
Fall, 2009
13
Special Consideration
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Grades are earned.
Grades are not awarded
Grades cannot be negotiated.
Grades cannot be influenced by factors such as:
I like you
You like me (rare circumstance)
I feel sorry for you
You are a nice person in good standing with the university.
You will lose a scholarship
You will forfeit some tuition reimbursement
A previously excellent GPA will be ruined
You will be sent back to a repressive country
You will not graduate on time!
Fall, 2009
14
Attendance
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Assumption: you are adult students
Attendance in lecture is expected
Do not ask me to re-lecture material you missed.
Regardless of your excuse for missing class you
made a choice not to attend and you are
responsible for the material you missed.
Attendance at examinations is required.
A missed examination will receive a zero.
No excuse will be accepted.
A missed final exam will receive a zero.
Fall, 2009
15
A Word on Examinations
• Examinations will consist of several short answer
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questions.
The final examination will contain 100 multiple
choice questions.
These will be similar to the questions
encountered on the MCAT, DAT, PCAT, etc.
Fall, 2009
16
A Word on the Final Exam
• The final exam is scheduled by the university.
• This schedule minimizes conflicts between
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rooms and courses.
If the scheduled date and time happens to be
inconvenient for you, please withdraw from
the course today.
There is no excuse that I will accept that
would permit you take the exam early.
Fall, 2009
17
Communication in Class
• Turn your cell phone off.
• Turn your desire to communicate with anyone
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but me off.
An offending cell phone (includes text
messaging) will result in the cancelation of that
day’s lecture.
If a class is cancelled because of an offensive
cell phone the class will be held responsible for
the material not covered me by in that class.
Fall, 2009
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Expectations - Students
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A professional student is expected to
attend class
purchase course materials
study
do the homework
be prepared for class
be prepared for tests
do well
Fall, 2009
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Expectations - Faculty
• I am expected to
• attend class
• prepare lecture materials
• present lecture materials
• prepare and grade tests
• be available for outside consultation
• keep accurate records
Fall, 2009
20
Important Note
• I am not expected to
• Provide extra credit
• Negotiate grades
Fall, 2009
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Doing Well
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Read the chapter before lecture
Attend lecture
Take notes
Do not rely on copies of Power Points
Re-read the chapter after lecture
Review lecture notes daily
Rewriting the lecture notes is strongly suggested
Keep, maintain, and study note cards
Do homework problems.
Form a study group
Learn the functional groups
Fall, 2009
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The Functional Groups
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Families of Organic Compounds
Millions of compounds
Thousands discovered every year
Task of knowing the chemistry would be overwhelming
However, compounds can be grouped into families
Based upon common structural features
Suggests common reactivity
You must know the Table of Functional Groups provide by me.
Others will come along during the semester
• This course is a survey the chemistry and properties of organic
compounds
• It is taught as a tour of the functional groups
Fall, 2009
23
Functional Groups
R
R
CH3
alkane
X
CH2
alkyl
R
R
halide
R
alkene
alkyne
(X = F,
Cl, Br, I
R
OH
R
R
S
R
R
S
O
sulfoxide
phenol
Fall, 2009
R
SH
sulfone
R
S
R
sulfide
thiol
O
O
O
OH
R
ether
alcohol
arene
O
R
R
S
OH
O
sulfonic
acid
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Functional Groups
O
O
H
R
R
O
R
R
carboxylic
acid
R
carboxylic
acid chloride
carboxylic acid
anhydride
O
O R
R
Cl
R
O
O
O
OH
R
ketone
aldehyde
O
O
ester
H3C
R
NH2
amide
N
nitrile
Fall, 2009
25
Wow!
• That’s a lot of stuff to learn and you
expect me to know it.
• Do you believe that this is the only course
I am taking?
• This is an important question which we
must answer!
• You may not like the answer.
Fall, 2009
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Is this the only course I am taking?
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YES
Time invested = Desired grade
Average professional – 60 hours/week
Professional student
~18 hours/week in class
60 – 18 = 42
42hours/6 days = 7 hours per day
Or approximately 2 hours/class
Time invested = Desired grade
Fall, 2009
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Why?
• Your Role:
• The job of understanding the material is yours.
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My Role:
Guide
I’ve been here.
I’ve done it.
I have the t-shirt (at least a C and a B in Organic I and II)
• Best advice I can give you!
• If you choose to study organic chemistry like other courses you
have taken you might do well, but the odds are against it.
Fall, 2009
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Major Complaint
• I can’t possibly learn this stuff.
• I can’t learn all of those functional groups.
• Why? Again you aren’t going to like the
answer.
• You don’t study enough.
• Average of 42 hours per week beyond
your class is expected
• To obtain a C - the average grade
Fall, 2009
29
Comment
• I have never met a student who could not
learn organic chemistry.
• Some students might make 3 or more
attempts to learn the material.
• The number of attempts required is
dependent upon you.
Fall, 2009
30
Why don’t students learn?
• Fear
• Wrong attributes
• Lack of confidence
• Too much confidence
• Failure to follow through
• Paralysis due to personal/family problems
• Failure to imitate best practices
• Lack of balance of social and academic life
• Failure to appreciate delayed gratification.
Fall, 2009
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Guide’s Role
You
Fall, 2009
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Study Sessions
• Study sessions will be held
• Tuesday and Thursday
• 7 – 8 AM
• They are not mandatory
• The first one will be held next Tuesday.
• The last one the first time I enter the
room and no one is here.
Fall, 2009
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Important Goals of
Organic Chemistry
• Prepare you for MCAT, DAT, OAT, etc.
• Assist in your transition from a student to
a scholar.
• This is done by
– Mastery of content
– Application of theoretical constructs
– Developing skills to critique, analyze,
research, discuss, write, and present.
Fall, 2009
34
What is the minimum I need to do
to get out of here?
• Depends, what grade do you want?
• W, F, or D
– Attend class irregularly
– Study just before each test
– Rely upon your memory
• C, B, or A
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Never miss class
Read the chapter before and after class
Review lecture notes daily
Study 2 hours per day, 6 days per week
Make and use note cards
Do all assigned homework problems
See me for assistance early and often
Fall, 2009
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Why Study Organic Chemistry?
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Required for Major
I will never need it.
Required for Major
I might need it someday.
Elective
I will certainly never need it.
Best course on campus.
Best instructor on campus
Only class available at this forsaken time
Need to lower my GPA.
Fall, 2009
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Who studies Organic Chemistry?
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Chemistry
Biology
Pre-medicine
Pre-dentistry
Pre-pharmacy
Animal Science
Pre-veterinarian
Nutrition
Other programs not offered at VSU also require
organic chemistry.
Fall, 2009
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A Common Thread
• Sciences
• Scientists do science
• Scientists do NOT do sloppy work
• Sloppy scientists fulfill Darwin’s principles!
Fall, 2009
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Some More Important Questions
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Is drop/add over?
Are there any other instructors available?
When is the last day to withdraw?
What is the minimum I need to pass?
What is organic chemistry?
Before we start, let’s review some general
chemistry concepts that are important for us
because organic chemistry depends upon a
fundamental understanding of general chemistry
Fall, 2009
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Important Note
• If you decide to withdraw from the lecture
• at any point in the semester,
• You must withdraw from the laboratory!
• Let’s review General Chemistry!
Fall, 2009
40
Review of General Chemistry
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To be here you met the pre-requisites.
You have taken General Chemistry I and II.
You have learned the following
The Periodic Table
Structure of the atom and electron configuration
Lewis dot structures and bonding
Basic chemical nomenclature
Stoichiometry
Energy and chemical reactions
Chemical equilibrium, acids, bases
Thermodynamics and basic kinetics
Assumption for Organic Chemistry I
You received an A in General Chemistry I and II.
Fall, 2009
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Review of General Chemistry
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Nucleus
Orbitals
Electronic Configuration
Chemical Bonding
Ionic and Covalent
Hybridization of Carbon’s Orbitals
sp3, sp2, and sp hybridization
Molecular Orbital Theory
Formation of C-C sigma and pi bonds
Fall, 2009
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Review of General Chemistry
• Electronegativity
• F is the most electronegative atom
• Electronegativity decreases down group
• Electronegativity decreases right to left
• Polar covalent bonding
• Dipole moments
• Formal Charge
Fall, 2009
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Review of General Chemistry
• Review Resonance
• Consider two structures
• Acetate ion and Benzene
Fall, 2009
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Acetate Ion
O
O
O
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O
Two line structures are possible
C=O and C-O bonds
However, both C-O bonds are 127pm
C=O is 120pm and C-O is 135pm
Fall, 2009
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Benzene
• Two possible line structures
• Neither is correct
• C-C bonds in benzene are all 139pm
• C-C bond is 154pm and C=C is 134pm
• Problem encountered
• Drawing these molecules
• True structure can’t be drawn
Fall, 2009
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Drawing these Structures
• We cannot draw the true structure
• Therefore, we invoke idea –
• resonance
• Individual structures are resonance
hybrids of true structure
• We cannot draw the true structure
Fall, 2009
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Resonance Structures
Resonance Hybrids
O
O
O
Fall, 2009
O
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Resonance Guidelines
• Individual resonance forms are not real
• Resonance forms differ only in placement
of electrons (pi or non-bonding)
• Resonance forms do not have to be
equivalent
• Resonance forms obey valence rules
• Hybrid is more stable than resonance
forms
Fall, 2009
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Review of Acids and Bases
• Two Definitions of Acids and Bases
• Bronsted-Lowry
• Lewis
Fall, 2009
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Bronsted – Lowry
• Acid donates a proton
• Base accepts a proton
• Consider following reaction:
HA + HOH
H3O+ + A[H3O+] [A-]
Keq =
Fall, 2009
[HA] [HOH]
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In dilute solution
• [HOH] = 55.5M, nearly constant
• Therefore, define the acidity constant
HA + HOH
H3O+ + A[H3O+] [A-]
[HOH] Keq =
[HA]
[H3O+] [A-]
Ka =
Fall, 2009
[HOH] Keq =
[HA]
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Acid Strength
HA + HOH
H3O+ + A-
Strong acids – equilibrium is to the right
Ka is large
Weak acids – equilibrium is to the left
Ka is small
Range of values is 1015 (strongest) to 10-60 (weakest)
Fall, 2009
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pKa Values
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pKa = -logKa
Values range -7 (strongest) to 60 (weakest)
As strength of acid increases
Strength of base decreases
HCl pka = -7 (a strong acid)
Conjugate base: Cl- is very weak
H-CH3 pKa = 60 (a weak acid)
Conjugate base CH3- is very strong
Fall, 2009
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A Few pKa Values
(learn this list as we will add to it)
• EtOH
• HOH
• HCN
• HOAc
• Phosphoric Acid
• Nitric Acid
• HCl
Fall, 2009
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15.7
9.3
4.8
2.2
-1.3
-7
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pKa Values
• Learn values given in Table 2.3 (p 52)
• Use these values to predict acid base reactions
• Consider the following:
HOAc + NaOH
NaOAc + HOH
Which is the stronger acid?
pKa of HOAc = 4.76
pKa of HOH = 15.7 (conjugate acid of NaOH)
HOAc = stronger acid than HOH, HO- = stronger base than AcOReaction proceeds to the right.
Fall, 2009
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Lewis Acids and Bases
• Lewis Acids – accept an electron pair
• Lewis Bases – donate an electron pair
• The electron pair ends up shared by the
acid-base as a covalent bond
Fall, 2009
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Lewis Acids
• The Lewis definition of acidity includes metal cations
• such as Mg2+
• Neutral Group 3A compounds
• such as BF3 and AlCl3
• Neutral transition-metal compounds
• such as TiCl4, FeCl3, ZnCl2, and SnCl4
• The combination of a Lewis acid and a Lewis base can
shown with a curved arrow from base to acid
Fall, 2009
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Lewis Bases
• Donate an electron pair
• Molecules must contain an electron pair
Fall, 2009
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Lewis Acids and Bases
• H+ is a Lewis acid
• Accepts electron pair from water
• Hydronium ion (H3O+)
• Water is a Lewis base
• Donates electron pair to the proton
Fall, 2009
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Illustration of Curved Arrows in Following
Lewis Acid-Base Reactions
Fall, 2009
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Review of General Chemistry
• Our review of general chemistry is done.
• We have also covered Chapters 1 and 2 in
• Organic Chemistry: A Biological Approach
by John McMurry
• Now, we can ask
• What is organic chemistry?
• Why am I studying this course?
Fall, 2009
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Organic Chemistry
• is the study of the chemistry of compounds that
contain carbon.
• Carbon is a unique element in the Periodic Table
in that
• (1) it likes to bond to itself and
• (2) The number of carbon atoms that can be
bonded in a chain appear to be limitless.
Fall, 2009
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Organic Chemistry and Biology
• Biological revolution
• Biotechnological advances
– Unprecedented scale
– Foundation is organic chemistry
• All organic molecules contain Carbon
• 99% of 26 million molecules contain C
• Possible because of Carbon’s electronic
structure
Fall, 2009
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Questions to consider in CHEM305
• Why do organic molecules have certain
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properties?
Why do certain reactions occur?
Why do other reactions not occur?
What drives these processes?
• Can we predict the presence or absence of
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certain properties?
Can we make new materials with other desired
properties?
Fall, 2009
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Biological Organic Chemistry
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Know what and why something happened
Molecular level
Understanding is based on foundation
Bonding
Bond polarity
Acid base behavior
Hydrogen bonding
Organic chemistry depends upon a fundamental
understanding of general chemistry
Fall, 2009
66
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