Transcript Functional Groups

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Organic chemistry: study of compounds that
are based on carbon.
◦ Usually contain carbon-carbon and hydrogencarbon bonds.
The Carbon Atom
 usually forms a total of 4 covalent bonds.
 Can form strong single bonds (_____ pair(s) of
electrons shared, double bonds (_____ pair(s)
of electrons shared), or triple bonds (______
pair(s) of electrons shared) with other
carbons.
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Saturated molecules: carbon atoms have
maximum bonding capacity of __________.
Molecules containing double or triple carboncarbon bonds are called ________________.
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Rules for drawing a 3-D molecule
◦ Let’s use methane, CH4, as an example.
◦ “Wedges” are used to give the impression that an
atom or group is coming forward.
◦ Dashed/dotted lines are used to show that an atom
or group is receding.
Which of the following bonds are polar? Non-polar?
C–O
C–C
O–H
C -H
N–H
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Polar Molecule: molecule has an overall
imbalance of _________________.
Not all molecules with polar bonds are polar
molecules. (e.g. CO2 has two polar C=O
bonds, but is not a polar molecule).
Is water a polar molecule?
1)
If equal bond dipoles act in opposite
directions in three-dimensional space, they
counteract each other. The molecule is
_________________________.
E.g. CCl4,
(four identical dipoles, pointing toward
the vertices of a tetrahedron, counteract
eachother  can prove mathematically)
If the bond dipoles in a molecule do not counteract
each other exactly, the molecule is
_________________.
E.g. Water
E.g. CHCl3 , chloroform
(bond dipoles do not act in opposite directions,
therefore, do not counteract each other, and
molecule is polar).
CLASSWORK
Read page 9, steps 1, 2 and 3.
Create a dichotomous key in order to
determine the polarity of the molecule, with
one example at each ‘end’ of each ‘branch.’
Read sample problem, pg. 10, and do
PPs # 1-4
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Page 11, #2, 4, 5
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Hydrocarbons: simplest type of organic
compound.
◦ Composed entirely of hydrogen and carbon.
◦ Widely used as fuels. E.g. Gasoline, propane, and
natural (non-polar).
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Aliphatic: carbon atoms bonded in one or
more chains and rings. Single, double, triple
bonds.
Aromatic: based on aromatic benzene group
(later!)
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Alkane: single bonds.
◦ Linear: CnH2n+2
◦ Cycloalkane: CnH2n
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Alkene: at least one double bond.
◦ Linear with one double bond: CnH2n.
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Alkyne: at least one triple bond.
◦ Linear with one triple bond: CnH2n-2.
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Double and triple bonds contain more than
one bond.
First bond is always strongest.
Second and third bonds are weaker:
therefore, react faster
◦ C=C bonds are ________________________ than C-C
bonds.
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Functional Group: reactive group
◦ Each group helps to determine the physical and
chemical properties of compounds.
◦ E.g. Reactive double bond of an alkene is the
functional group.
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The International Union of Pure and Applied Chemistry (IUPAC)
has standard rules for naming organic compounds
PREFIX + ROOT + SUFFIX
Root
- Number of carbons in the main chain/ring.
Suffix
- Depends on functional group present.
- E.g. –ane, -ene, and –yne. (there are many others)
Prefix
- Indicates the name and location of each branch and functional
group in the main carbon chain.
- Alkyl groups: branches on main chain.
1)
Find the root: identify the longest chain or ring.
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If cyclic compound, add prefix –cyclo- before the root.
2) Find the suffix: -ane, -ene, and –yne.
- if more than one double/triple bond, use prefix di-,
tri- before suffix.
3) Number the carbons
- start at end giving the lowest possible number for the
double or triple bond OR
- start at end giving the lowest possible number for the
branches.
4) Find the prefix
- name each branch as an alkyl group with position
number.
- if more than one branch, list in alphabetical order.
- put the position number of any double or triple bonds
after the position numbers and names of the branches,
just before the root.
5) Put the name together: prefix + root + suffix.
The main chain has ___ C. Root: _________
2) Only ___________ bonds. Suffix:_________
3) A _____________ group is attached to carbon
__________. Prefix: ____________
5) Full name: ____________________________.
1)
Main ring (____________) has ___ Cs.
Root: ______________.
2) Only _____________ bonds. Suffix: ______.
3) And 4) A(n) ______________ group is attached
to carbon _____. Prefix: ________.
5) Full name: __________________________.
1)
Main chain has _____ C. Root: ___________.
2) Contains one ________ bond. Suffix: ______.
3) Two __________ groups on carbon
___. One ____________ group on carbon ___.
The = bond is at carbon _____.
Prefix: ________________________________.
5) Full name: __________________________.
1)
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Use hyphens (-) to separate words from
numbers.
Use commas to separate numbers from each
other.
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Draw a condensed structural diagram for
1-ethyl-2-methylhexane.
Build one of the following hydrocarbons:
 3-ethyl-2, 3, 4-trimethylnonane (SR, #2 d)
 3-methyl-2,4,6-octatriene (PP #6, c)
 4-ethyl-3-methylheptane (PP #6, b)
Large balls count as carbons.
Small balls count as hydrogen.
Carbons in the MAIN CHAIN do not require
hydrogens (will take up too much room).
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Aromatic Compound: have a special form of sharing of
electrons, such as benzene.
Benzene
◦ Cyclic compound with three double bonds and three single bonds.
◦ Wacky molecule: electrons that form double bonds in benzene are
spread out and shared over the whole molecule.
◦ Therefore, six identical bonds, each one half-way between single
and double.
Page 20.
#1, 2, 3, 6.
Functional Group: a group of bonded atoms in
an organic compound that reacts in a
characteristic way.
E.g.
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General Formula: the general formula for a
family of organic compounds is R +
Functional group.
◦ R: any alkyl group.
◦ E.g. R – OH
1)
2)
Compounds with the same
functional group often have
similar properties.
Compounds with the same
functional group react
chemically in very similar
ways.
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Similar boiling points, melting points, and
solubilities.
Due to intermolecular forces: forces of
attraction and repulsion between particles.
◦ Hydrogen Bonding: strong intermolecular attraction
between H atom of N-H, O-H, or F-H group on one
molecule, and N, O, or F on another.
◦ Dipole-dipole interactions: polar molecules are
attracted to eachother.
◦ Dispersion forces: occurs between all covalent
molecules due to temporary dipoles.
1) What kinds of molecules are usually soluble in water? Why do
you think this is?
2) Do polar or non-polar molecules usually have a higher
boiling point? Why?
3) Substances A and B are both pure substances composed of
polar molecules. Substance A also has the ability to hydrogen
bond. Which one has a higher boiling point?
4) Polar molecules with a _____________ non-polar hydrocarbon
part are less polar than polar molecules with a smaller nonpolar hydrocarbon part.
5) Polar molecules with a large hydrocarbon part are less
____________ in water than polar molecules with a smaller
hydrocarbon part.
7) Dispersion forces are stronger when
_____________________________________
________________________________________________.
See page 24 of your Textbook.
Follow the procedure and answer the questions
in the thought lab.
Report is due next class.
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Alcohols
Alkyl halides
Ethers
Amines
1) Alcohols
 Contains the –OH functional group.
 Can be primary, secondary, or tertiary
depending on the position of the hydroxyl
group.
Naming an Alcohol:
Read page 26 and go through SP.
Do PP # 14, 15, 16.
Alkyl Halides
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One or more hydrogen atoms replaced with
halogen atoms: F, Cl, Br, or I.
Functional group is R –X (x represents halogen).
Physical Properties of Alkyl Halides
 similar to alcohols.
Naming an Alkyl Halide:
Read page 28, and do SP.
Do PPs 18 – 21.
Ethers
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An organic compound that has two alkyl
groups joined by an oxygen atom.
R–O–R
Think of alcohols and ethers as derivatives of
the water molecules:
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Ether examples:
How to Name an Ether
Read pg. 29 and do SP on pg. 30
PPs 22-24
Physical Properties of Ethers
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Amines
- NH2, - NHR, -NR2, where R is an alkyl group
attached to the nitrogen.
General formula: R – NR’2
Thought of as derivatives of the ammonia
molecules, NH3.
Classified as primary, secondary, or tertiary,
depending on how many alkyl groups attached to
the nitrogen atom.
How to name an Amine:
Read Page 31. Do SP on pg. 32
PPs. 26-28
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Finish all PPs not finished in class.
SR 1, 2, 3, 5, 6, 7, 8.
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C=O: Carbonyl Group
Functional Groups with C=O bond
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Aldehydes
Ketones
Carboxylic Acids
Esters
Amides
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An organic compound that has a doublebonded oxygen on the last carbon of a
carbon chain.
General Formula: R-CHO
To name an Aldehyde:
1) Name the parent alkane.
2) Carbon atom of carbonyl group is C1.
3) Replace –e at the end of the parent alkane
with –al.
4) Do not need to include position number for
carbonyl group.
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Organic compound that has a double-bonded
oxygen on any carbon within the carbon
chain.
General Formula: RCOR’
To name a ketone:
1) Name the parent alkane. Main chain must
contain C=O group.
2) One ketone group: replace –e with –one.
More than one: keep –e suffix and add –
dione or –trione.
3) For carbon chains with more than four
carbons, position number needed. Carbonyl
group has lowest position number.
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An organic compound with the following
functional group:
-COOH
General Formula: R-COOH.
Naming Carboxylic Acids
1) Name parent alkane
2) Replace –e with –oic acid.
3) Carboxyl group is always position 1.
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A derivative of a carboxylic acid.
General Formula: RCOOR’
Notice that the H of the carboxylic acid is
replaced by R’.
Naming an Ester
1)
Identify main part of ester containing C=O group.
Name this parent acid.
2)
Replace the –oic acid with –oate.
3)
Identify the part of the ester that is attached to
the oxygen atom. Name it as an alkyl group.
4)
Put the two names together.
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Organic compound that has a carbon atom doublebonded to an oxygen atom and single-bonded to a
nitrogen atom.
General formula: R-CO-NR2, where R can be H or
an alkyl group.
Naming Amides
1) Locate part of amide with C=O group. Name this
parent carboxylic acid.
2) Replace –oic acid with suffix –amide.
3) Decide whether primary, secondary, or tertiary.
1) If two H on nitrogen atom, primary (no prefixes
needed)
2) If one alkyl group attached to nitrogen, secondary.
Name alkyl and give location letter N3) If two alkyl groups attached to nitrogen, tertiary. Place
alkyls in alphabetical order and give location number
N- or N,N- if alkyls identical.
Complete questions
#1, 3, 4, 5, 6, 7.
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Page 52 (You should go back through your
notes/textbook)
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Understand ALL Key terms
Knowledge/Understanding: #3-17
Inquiry: #18 (to hand in next class)
Communication: #19-22 (understand the idea
behind #23 & 24)