Download 10.1 Intro to Organic Chemistry 10.1 Organic Chemistry

Organic Chemistry:
Introduction
IB Topic 10
10.1 Introduction
10.1.1 Describe the features of a homologous series.
10.1.2 Predict and explain the trends in boiling points of
members of a homologous series.
10.1.3 Distinguish between empirical, molecular and
structural formulas.
10.1.4 Describe structural isomers as compounds with the
same molecular formula but with different arrangement
of atoms.
10.1.5 Deduce structural formulas for the isomers of noncyclic alkanes up to C6.
10.1.6 Apply IUPAC rules for naming the isomers of the
non-cyclic alkanes up to C6.
What is organic chemistry?
Organic Chemistry


The study of carbon, the compounds it
makes and the reactions it undergoes.
Over 16 million carbon-containing
compounds are known.
What is organic chemistry?
Carbon




Carbon can form multiple bonds to itself
and with atoms of other elements.
Carbon can only make four bonds since it
has 4 valence electrons and most often
bonds to H, O, N and S.
Because the C-C single bond (348 kJ mol1) and the C-H bond (412 kJ mol-1) are
strong, carbon compounds are stable.
Carbon can form chains and rings.
What is organic chemistry?
Hydrocarbons


Hydrocarbons are organic compounds that
only contain carbon and hydrogen
Types of hydrocarbons include
 Alkanes
 Alkenes
 Alkynes
 Aromatic
10.1.1

Describe the features of a homologous
series.
A homologous series is a series of related
compounds that have the same functional
group.


Differ from each other by a CH2 unit
Can be represented by a general formula

examples:
 CnH2n+2 (alkanes) or CnH2n (alkenes) or…
10.1.1
Describe the features of a homologous
series.
Watch out!!! Homologous
compounds DO NOT have the
same empirical formula!
•
•
Have similar chemical properties
Have physical properties that vary in a
regular manner as the number of
carbon atoms increases
–
Example: the alkanes
#C
Prefix
Alkane (ane)
Alkene (ene)
CnH2n+2
CnH2n
1
meth
CH4
methane
2
eth
C2H6
ethane
3
prop
4
but
5
pent
6
hex
C2H4
ethene
10.1.2
Predict and explain the trends in
boiling points of members of a homologous series.
What is the trend?
Why?
Alkane
Formula
Boiling
Pt./oC
methane CH4
-162.0
ethane
C2H6
-88.6
propane C3H8
-42.2
butane
-0.5
C4H10
Trends in boiling points of members of a
homologous series (10.1.2)
• Melting point and
boiling point increase Alkane Formula Boiling
Pt./oC
with more carbon
atoms
methane CH4
-162.0
• Why?
–
–
intermolecular
forces increase
adding a CH2 adds
more electrons
•
this increases the Van
der Waal’s forces
ethane
C2H6
-88.6
propane C3H8
-42.2
butane
C4H10
-0.5
10.1.2
Predict and explain the trends in
boiling points of members of a homologous series.

Intermolecular forces present




Simple alkanes, alkenes, alkynes → van der
Waals’ forces (nonpolar) → lower b.p.
Aldehydes, ketones, esters & presence of
halogens (polar) → dipole: dipole forces →
slightly higher b.p.
Alcohol, carboxylic acid & amine → hydrogen
bonding (w/ O, N, F) → even higher b.p.
Naming song:
https://www.youtube.com/watch?v=mAjrnZ-znkY
10.1.2
Predict and explain the trends in
boiling points of members of a homologous series.
10.1.3
Distinguish between empirical,
molecular and structural formulas.
Empirical Formula:
Smallest whole number
ratio of atoms in a
molecule
Molecular Formula:
Formula showing the
actual numbers of
atoms
Molecular
Formula
Empirical
Formula
CH4
CH4
C2H6
CH3
C6H12O6
C4H8
C8H16
10.1.3
Distinguish between empirical,
molecular and structural formulas.



Structural Formula
Bond angles are drawn as though 90o. The true shape
around C with 4 single bonds is tetrahedral and the
angle is 109.5o.
Show every atom and every bond. Can use condensed
structural formulas.
Hexane: CH3CH2CH2CH2CH2CH3 (condensed s.f.)
M.F. = C6H14
E.F. = C3H7
Structural formula


Structural formula
Can use condensed structural formulas
 bonds are omitted, repeated groups put
together, side chains put in brackets
 CH3CH2CH2CH2CH2CH3
 or even CH3(CH2)4CH3
 CH3CH(CH3)CH3
10.1.3
Distinguish between empirical,
molecular and structural formulas.
Skeletal formula
–
–
–
Not accepted in the IB for answers but often
used in questions… cuz that’s how they do it
Every “corner” represents a carbon
Hydrogens are implied
10.1.4
Describe structural isomers as
compounds with the same molecular formula but
with different arrangement of atoms.


Structural isomers: compounds with the same
molecular formula, but different arrangement of
atoms
The Fuse School:
https://www.youtube.com/watch?v=9SX-iWpi98g
10.1.4
Describe structural isomers as
compounds with the same molecular formula but
with different arrangement of atoms.
•
•
Different isomers are completely different
compounds
Have different physical properties such as
melting point and boiling point
Structural
Formulas
for C4H10O
Isomers
10.1.5
Deduce structural formulas for the
isomers of non-cyclic alkanes up to C6.

You should be able to draw out and write the
structural formulas for all isomers that can be
formed by:







CH4
C2H6
C3H8
C4H10
C5H12
C6H14
Eventually you should be able to name all isomers, as
well
10.1.5
Deduce structural formulas for the
isomers of non-cyclic alkanes up to C6.

If there is a branch off of the main chain,
put that formula in parentheses

CH3CH(CH3)CH3

CH3CH2CH2CH3
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
Determine the longest carbon chain
Use the prefix (next slide) to denote the number
carbons in the chain
1.
2.
1
2
3
4
5
6
MethEthPropButPentHex-
Monkeys
Eat
Peanut
Butter
3.
4.
Use the suffix “-ane” to indicate that the substance
is an alkane
Number the carbons in the chain consecutively,
starting at the end closest to a substituent
(groups attached to the main chain/most busy
end)
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
Methylpropane
Methylbutane
Dimethylpropane
10.1.6 Apply IUPAC rules for naming the isomers
of the non-cyclic alkanes up to C6.
1
Meth-
6
Hex-
2
Eth-
7
Hept-
3
Prop-
8
Oct-
4
But-
9
Non-
5
Pent-
10
Dec-
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
For chains longer than 4 carbons with side chains:
5.
name and number the location of each
substituent

the name of the substituent will be written before the
main chain and will end with “–yl” (or just memorize the
below)



CH3 is methyl
C2H5 is ethyl
C3H7 is propyl
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
And with 2 or more side chains:
6.
Use prefixes di-, tri-, tetra-, to indicate when there are
multiple side chains of the same type.
7.
Use commas to separate numbers and hyphens to
separate numbers or letters.
8.
Name the side chains in alphabetical order.
WHEW!!!!!!!!

How about C5H12? The isomers are:
Pentane
2-methyl-butane 2,2-dimethyl propane
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
9 carbons = nonane
6
7
8
H3C9
Step #1: For a branched hydrocarbon, the longest continuous
chain of carbon atoms gives the root name for the
hydrocarbon
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
6
9 carbons = nonane
CH3 = methyl
7
8
chlorine = chloro
H3C9
Step #2: When alkane groups appear as substituents, they are named
by dropping the -ane and adding -yl.
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
9 carbons = nonane
CH3
6
CH3 = methyl
7
chlorine = chloro
8
H3C9
1
9 NOT
9
1
Step #3: The positions of substituent groups are specified
by numbering the longest chain of carbon atoms
sequentially, starting at the end closest to the
branching.
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
9 carbons = nonane
6
CH3 = methyl
7
8
chlorine = chloro
H3C9
2-chloro-3,6-dimethylnonane
Step #4: The location and name of each substituent are
followed by the root alkane name. The substituents are
listed in alphabetical order (irrespective of any prefix), and
the prefixes di-, tri-, etc. are used to indicate multiple
identical substituents.

What about boiling points of isomers???
Pentane
2-methyl-butane 2,2-dimethyl propane

Magnitude of the force depends on…
Number of electrons and size of the
electron cloud
1.

with more electrons, valence electrons are
farther away from the nucleus and can be
polarized more easily
Shape of molecules
2.

molecules with shapes that have more
contact area have greater forces between
them than those don’t
these round
shapes do NOT
allow them to
stick to one
another
this flat shape
allows it to
stick to one
another better
boiling point increases
10.1 Introduction, cont.
10.1.7 Deduce structural formulas for the isomers of the straightchain alkenes up to C6.
10.1.8 Apply IUPAC rules for naming the isomers of the straight-chain
alkenes up to C6.
10.1.9 Deduce structural formulas for compounds containing up to six
carbon atoms with one of the following functional groups: alcohol,
aldehyde, ketone, carboxylic acid and halide.
10.1.10 Apply IUPAC rules for naming compounds containing up to six
carbon atoms with one of the following functional groups: alcohol,
aldehyde, ketone, carboxylic acid and halide.
10.1.11 Identify the following functional groups when present in
structural formulas: amino (NH2), benzene ring (
) and esters
(RCOOR).
10.1.12 Identify primary, secondary and tertiary carbon atoms in
alcohols and halogenoalkanes.
10.1.13 Discuss the volatility and solubility in water of compounds
containing the functional groups listed in 10.1.9.
10.1.7
Deduce structural formulas for the
isomers of the straight-chain alkenes up to C6.



Remember that structural formulas show the relative location of
atoms around each carbon
Hexane: CH3CH2CH2CH2CH2CH3 (condensed s.f.)
M.F. = C6H14
Determine the molecular formulas for the alkenes below. Draw out
and write the structural formulas for all isomers that can be formed
by each.
 C2H4
 C3H?
 C4H?
 C5H?
 C6H?
10.1.8
Apply IUPAC rules for naming the
isomers of the straight-chain alkenes up to C6.
Alkenes have a double bond between two or more of
the carbons
 CnH2n
 Draw out and write the structural formulas for all
isomers that can be formed by each
– C2H4
– C3H6
– C4H8
– C5H10
– C6H12

45
Naming the isomers (IUPAC) of straight chain
alkenes up to C6 (10.1.8)
1.
suffix changes to “-ene”
2.
when there are 4 or more carbon atoms in a
chain, the location of the double bond is
indicated by a number
3.
begin counting the carbons closest to the
end with the C=C bond

numbering the location of the double
bond(s) takes precedence over the location
of any substituents
1-butene
but-1-ene
2-butene
but-2-ene
10.1.8
Apply IUPAC rules for naming the
isomers of the straight-chain alkenes up to C6.
Breakin’ it down…
1.
2.
3.
Count the number of carbons in a chain
Determine the ending of the name,
based on # of bonds or functional
group
Determine any side chains, which will
be placed at the front of the name
48
Naming Practice!!!
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
choose the correct ending
ene
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
determine the longest carbon chain with
the double bond
ene
CH2
CH3 CH2 C
CH2 CH3
CH2 C
CH3
CH3
assign numbers to each carbon
ene
CH2
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
6
CH3
CH3
assign numbers to each carbon
ene
CH2
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
6
CH3
CH3
attach prefix (according to # of carbons)
1-hexene
ene
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
determine name for side chains
1-hexene
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
attach name of branches alphabetically
2-ethyl-4-methyl-4-methyl-1-hexene
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
group similar branches
2-ethyl-4-methyl-4-methyl-1-hexene
CH2
ethyl
CH2 CH3
1
CH3 CH2 C
2
5
CH2 C
3
4
CH3
6
CH3
methyl
methyl
group similar branches
2-ethyl-4,4-dimethyl-1-hexene
or 2-ethyl-4,4-dimethyl hex-1-ene
CH3 CH
CH2
propene
CH3 CH
CH3
CH3
CH
CH3
CH
C
CH3
CH CH3
2-butene
2,4-dimethyl-2-pentene
2,4-dimethyl pent-2-tene
CH3
CH2 CH
C
CH3
CH2 CH3
CH3
CH3
C
CH
CH2
a) 3,3-dimethyl-1-pentene
C
C
CH
CH3
b) same
CH3
CH3
CH2
CH
CH3
c) 4,5 dimethyl-2-hexene
CH3
Organic Chemistry Introduction:
Functional Groups
Topic 10.1.9 – 10.1.13
10.1.9 Deduce structural formulas for compounds containing up
to six carbon atoms with one of the following functional groups:
alcohol, aldehyde, ketone, carboxylic acid and halide.


Functional group: a group of atoms that
defines the structure of a family and
determines its properties
The functional group concept explained: The
Chemistry Journey: The Fuse School:
https://www.youtube.com/watch?v=nMTQKBn2I
ss
10.1.10 Apply IUPAC rules for naming compounds containing up to six
carbon atoms with one of the following functional groups: alcohol,
aldehyde, ketone, carboxylic acid and halide.
Functional
Group
Alcohol
Aldehyde
Formula
-OH
-COH (on the end
Structural
Formula
-O–H
O
of a chain)
-C–H
Ketone
-CO- (can’t be on O
end of chain)
-C–
Carboxylic Acid -COOH (on the
O
end of a chain)
-C–O–H
Halide
-Br, -Cl, -F, -I
-X
10.1.10 Apply IUPAC rules for naming compounds containing up to six
carbon atoms with one of the following functional groups: alcohol,
aldehyde, ketone, carboxylic acid and halide.
Functional
Group
Formula
Suffix
(or Prefix)
-ol
Alcohol
-OH
Aldehyde
-COH (on the
end of a chain)
Ketone
-CO- (can’t be on -one
end of chain)
Carboxylic Acid
-COOH (on the
end of a chain)
-oic acid
Halide
-Br, -Cl, -F, -I
bromo-,chloro-,
fluoro-,iodo-
-al
Know these 7, only
have to recognize the
3 in the
Alcohols: suffix = “ol”
propan-1-ol
propan-2-ol
2-methyl propan-2-ol
Aldehydes: suffix = “al”
propanal
Note: an aldeyhde group is
always on an end carbon so
don’t need a number
butandianal
Ketones: suffix = “one”
propanone
(don’t need C#, must be in
between two carbons)
butanone
(don’t need C#, must be in
between two carbons)
2-pentanone or
pentan-2-one
butandione
pentan-3-one
Carboxylic Acids:
suffix = “oic acid”
butanoic acid
Note: a carboxyl is
always on an end
carbon
propandioic acid
Halides: prefixes = “fluoro, chloro, bromo, iodo”
1-bromopropane
2-chlorobutane
1,2-diiodoethane
1,2-difluoroethene
1,2-difluoroethene
1,1,2-trifluorothene
Only identify the following functional
groups in structures: (10.1.11)
Functional
Formula
Group
Amine
- NH2
Ester
Benzene
O
R–C–O–R
amino, benzene ring, ester
Functional Groups
Identify each functional group
by name…
This is a possible idea for
making flash cards.
10.1.11
Identify the following functional groups
when present in structural formulas: amino (NH2),
benzene ring (


) and esters (RCOOR).
Esters are used for fragrances and
flavoring agents since one of their major
properties is smell
Benzene is in a family known as the
aromatic hydrocarbons… because they
smell 
10.1.12 Identify primary, secondary and tertiary
carbon atoms in alcohols and halogenoalkanes.
With reference to the carbon that is directly
bonded to an alcohol group or a
halogen:
 Primary = carbon atom is only bonded to
one other carbon
 Secondary = carbon atom is bonded to
two other carbons
 Tertiary = carbon atom is bonded to
three other carbons
10.1.12 Identify primary, secondary and tertiary
carbon atoms in alcohols and halogenoalkanes.
Draw a…
 Primary alcohol
 Secondary halogenoalkane
 Tertiary alcohol
 What type are all aldehydes / carboxylic
acids? Why?
 What type are all ketones? Why?
10.1.13 Discuss the volatility and solubility in water of
compounds containing the functional groups listed in 10.1.9.

Volatility: how easily a substance turns
into a gas
The weaker the intermolecular force, the
more volatile it is
 So, is a nonpolar or polar substance more
volatile?
ionic › hydrogen bonding › dipole-dipole › van
der Wall’s (Fig. 10.35 for reference)
Therefore, volatility:





vdW › d-d › H
alkane › halogenoalkane › aldehyde › ketone › amine
› alcohol › carboxylic acid
10.1.2
Predict and explain the trends in
boiling points of members of a homologous series.

Intermolecular forces present




Simple alkanes, alkenes, alkynes → van der
Waals’ forces (nonpolar) → lower b.p.
Aldehydes, ketones, esters & presence of
halogens (polar) → dipole: dipole forces →
slightly higher b.p.
Alcohol, carboxylic acid & amine → hydrogen
bonding (w/ O, N, F) → even higher b.p.
Naming song:
https://www.youtube.com/watch?v=mAjrnZ-znkY
10.1.13 Discuss the volatility and solubility in water of
compounds containing the functional groups listed in 10.1.9.



Solubility: a solute’s ability to dissolve in a polar
solvent (water)
The more polar a substance is, the more soluble
it is
Solubility:




If the functional group is soluble (hydrogen bonded),
it will be more soluble
Solubility decreases as chain length increases
Smaller alcohols, aldehydes, ketones & carboxylic
acids are typically soluble
Halogenoalkanes are NOT soluble since they don’t
form hydrogen bonds
10.1.13 Discuss the volatility and solubility in water of
compounds containing the functional groups listed in 10.1.9.
1.
2.
3.
4.
Which substance is most soluble: ethene,
propene, prop-1-ene or hex-1-ene?
Rank the following substances in order of
increasing boiling point: C5H12,
CH3CH2CH2CH2OH, CH3OCH2CH2CH3
Compare the boiling points of C2H6, CH3OH
and CH3F
Explain, at the molecular level, why ethanol is
soluble in water, but cholesterol (C27H45OH)
and ethane are not.