Organic Chemistry First Test

What is Organic Chemistry?
-the study of compounds derived from living
organisms.
What is the problem with “Vital Force”?
Synthesized urea had the exact same properties as urea from natural sources.
According to vitalism, these compounds would not be similar, but modern thought has concluded that both compounds are exactly the same.
What is The Octet Rule?
atoms transfer or share electrons in such a way to attain a filled
shell of electrons.
Ionic Bonds:
-The attraction of two oppositely charged particles.
-ionic compounds are composed of an anion (-’ve) and a cation
(+’ve) that are attracted to one another
Covalent bonds:
bonds that are formed from the sharing of 2 electrons and the
overlap of orbitals.
What is a hetero-atomic bond?
-An unequal sharing of the electrons can
occur to provide polar covalent bonds.
-Unequal electron distribution about a molecule results in a dipole moment.
What is a Formal Charge?
The charge of an atom within a Lewis Structure (basically what is the
difference in number of e- for a free atom vs. the atom in a structure).

Formal charge= [group #] – [nonbonding atoms] – 1/2 [shared electrons]

What type of molecules are usually Ionic?
Acids and Bases
What is Resonance?
The actual structure.

-Only e- can be transfered.

What is the ‘s’ orbital defined as?
a standing wave (trident) that simply vibrates up (+) and
down (-).
What is the ‘p’ orbital defined as?
a standing wave (trident) that is separated by a node and
the two halves vibrates up (+) and down (-) out of phase.
Molecular Orbitals (overlapping)
Two atomic orbitals overlap to form two molecular orbitals:
1) Bonding molecular orbital (lower energy)
– Which we will discuss 99.9% of time
2) Nonbonding molecular orbital (higher energy)
What is sigma bonding?
-Electron density is centered directly between nuclei
-These are single bonds or the first bond of a multiple bond
What is pi bonding?
-Results from the overlap between two p oribtals
with electron density above and below bond axis
-These are the 2nd or 3rd bonds of a multiple bond
-‘Sideways overlap’
What are the General Rules of Hybridization?
1. Both sigma bonding e- and lone pair e- can occupy hybrid orbitals.
– The number of hybrid orbitals is computed by adding the number of sigma
bonds to the number of lone pair e- on the atom.
2. Use the hybridization and geometry to provide the largest amount of space for
the e-.
– sp (2 areas of e- density; 180o; Linear)
– sp2 (3 areas of e- density; 120o ; Trigonal)
– sp3 (4 areas of e- density; 109.5o ; Tetrahedral)
3. If 2 or 3 pairs of e- form multiple bonds, the first of the bonds is a sigma bond,
formed by the overlap of a hybrid orbital; the 2nd and 3rd bonds are pi bonds
and come from the overlap of unhybridized p orbitals.
What does Polarizability do?
It tends to increase with molecular weight and also
depends on molecular arrangements (isomers).
What are Dipolar Forces?
attractive force that exists between the positive end of one polar molecule
and the negative end of the other.
What is Hydrogen bonding?
attractive dipolar forces
between molecules in which hydrogen atoms are
covalently bonded to very electronegative elements
(O, N or F).
How does one define a `general alkane`?
-ALL SINGLE BONDS
What’s the name of the alkane that only contains 1 carbon?
methane
What’s the name of the alkane that only contains 2 carbons?
Ethane
What’s the name of the alkane that only contains 3 carbons?
propane
What’s the name of the alkane that only contains 4 carbons?
butane
What’s the name of the alkane that only contains 5 carbons?
pentane
What’s the name of the alkane that only contains 6 carbons?
hexane
What’s the name of the alkane that only contains 7 carbons?
heptane
What’s the name of the alkane that only contains 8 carbons?
octane
What’s the name of the alkane that only contains 9 carbons?
nonane
What’s the name of the alkane that only contains 10 carbons?
decane
First Rule of IUPAC
Determine the longest continuous chain of carbon atoms in molecule.
-This is the base name (i.e. hexane, pentane, butane, etc.)
-When two choices are available, choose the main chain with the highest
number of substituents.
Second Rule of IUPAC
Number the carbon atoms in the longest chain, beginning with
the end of the chain nearest a substituent.
Third Rule of IUPAC
Any substituent connected to the longest chain is named as the alkyl (-ane -> -yl) group and the location of this substituent is provided by the number of the carbon on the main chain it is
connected to.
• This is the name for the branch (i.e. hexyl, pentyl, butyl, etc.)
Forth Rule of IUPAC
When two or more substituents are present, list them in alphabetical order. When two or more of the same alkyl substituents are present, use the prefixes di-, tri-, tetra-, etc. to avoid having the same alkyl group twice.
What are the two conformations of Alkanes?

What are the three positions they can be in?

– Sawhorse Structure & Newman Structure

-Eclipsed, Straggered, or Skewed

What is the most stable conformation for cyclohexane?
the `chair` form
What is a`Resonance HYBRID`?
A single Lewis Structure that cannot completely describe a compound.
What is the `Major Contributing Structure`?
The structure that is the lowest in Energy , filled octets, and least formal charge/
What is an Arrhenius Acid/Base?
Acid- substance that provides H+

Base- substance that provides OH-

What is a Bronstead-Lowry Acid/Base?
Acid- a species that can donate a proton (H+)

Base- a species that can accept a proton (H+)

pH=?

[H+]=?

pH=-log[H+]

[H+]=10^-pH

When discussing Acid Strength, the “___” the pKa, the “___” the acid.
When discussing Acid Strength, the “LOWER” the pKa, the “STRONGER” the acid.
Ka=?
Ka=[H+][A-]/[HA]
What are the three factors that are used to predict Acid Strength?
1) Electronegativity
2) Anion Size
3) Resonance
Define Lewis Acids/Bases.
Acids- accepts e- pairs to form bonds.

Bases- donates e- pairs to form bonds.

What is an `Electrophile`?
Lewis Acid- “lover of e-“
What is a `Nucleophile`?
Lewis Base- “Lover of the Nucleus”
What are Isomers?
different compounds that can be formed with the molecular formula.
What is a Steroisomer?
isomers that differ only in the arrangement of atoms in space.
Define Solubility.
“Likes Dissolve Likes”
What are `Alkenes`?
-CONTAIN DOUBLE BONDS
What are `Alkynes`?
-TRIPLE BONDS
What are `Aromatics`?
hydrocarbons with very stable bonding.
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