Download Organic 10.1 SL

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. Homologous
compounds…




Differ from each other by a – CH2 – unit
(methylene group)
Can all be represented by a general formula
Have similar chemical properties
Have physical properties that vary in a regular
manner as the number of carbon atoms
present increases
#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
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.
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
formula
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
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.


Isomers: different compounds that have
the same molecular formula
Structural isomers: an isomer in which
the atoms are joined in a different order
so that they have different structural
formulae
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 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
10.1.5
Deduce structural formulas for the
isomers of non-cyclic alkanes up to C6.

Draw out and write the structural formulas
for all isomers that can be formed by:



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
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
1.
2.
3.
4.
Determine the longest carbon chain
Use the prefix (next slide) to denote the number
carbons in the chain
Use the suffix “-ane” to indicate that the substance
is an alkane
If the chain is branched, the name of the side
chain will be written before the main chain and will
end with “–yl”
10.1.6 Apply IUPAC rules for naming the
isomers of the non-cyclic alkanes up to C6.
Methylpropane
Methylbutane
Dimethylbutane
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.
Number the carbons in the chain consecutively, starting
at the end nearest side chains.
6.
Designate the location of each substituent group by an
appropriate number and name.
And with 2 or more side chains:
5.
Use prefixes di-, tri-, tetra-, to indicate when there are
multiple side chains of the same type.
6.
Use commas to separate numbers and hyphens to
separate numbers or letters.
7.
Name the side chains in alphabetical order.
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.

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Alkenes have one (or more) carbon to carbon double
bonds
Suffix changes to “-ene”
When there are 4 or more carbon atoms in a chain, the
location of the double bond is indicated by a number.
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 side chains
1-butene
2-butene
methylpropene
25
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
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
Alcohol
Aldehyde
Formula
-OH
Structural
Formula
-O–H
-COH (on the
O
end of a chain) - C – H
Ketone
- CO – (not on
O
the end)
-C–
Carboxylic Acid -COOH
O
-C–O–H
Functional Groups
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
Alcohol
-OH
Suffix
(or Prefix)
-ol
Aldehyde
-COH
-al
Ketone
- CO -
-one
Carboxylic
Acid
Halide
-COOH
-oic acid
-Br, -Cl, -F, -I
Bromo-,
10.1.11
Identify the following functional groups
when present in structural formulas: amino (NH2),
benzene ring (
) and esters (RCOOR).
A few more groups:
Functional
Formula
Group
Amine
- NH2
Ester
Benzene
O
R–C–O–R
Ethyl ethanoate
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
10.1.13 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

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The weaker the intermolecular force, the
more volatile it is
So, is a nonpolar or polar substance more
volatile?
Solubility: a solute’s ability to dissolve in a
polar solvent (water)

The more polar a substance is, the more
soluble it is
10.1.13 Discuss the volatility and solubility in water of
compounds containing the functional groups listed in 10.1.9.

Volatility:
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vdW › d-d › H
alkane › halogenoalkane › aldehyde › ketone › amine
› alcohol › carboxylic acid
Solubility:


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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