chemistry 11 – aromatic compounds study...
TRANSCRIPT
1
Chemistry 11 – Hydrocarbon Alkane Notes
In this unit, we will be primarily focusing on the chemistry of carbon compounds, also known as ____________________________. Why is organic chemistry so important?
x Many of the compounds that surround us in everyday life are made up of organic compounds. Some are found naturally, while others are produced synthetically.
x Some examples include:
Æ C8H18 ______________________________
Æ CH4 ______________________________
Æ C17H21NO4 ______________________________
Æ C10H14N2 ______________________________
Æ C6H12O6 ______________________________
What are organic compounds primarily made of?
x As you can see from the examples above, organic compounds of mostly made of two types atoms. They are ______________ and ________________!
x Hydrocarbon: ________________________________________________________
x Before we go any further, we must become familiar with Carbon!
Æ Carbon has ____ electrons in its outer shell, so it can form ____ (and only ____)
bonds with other elements. Hydrogen atoms usually attach to the carbons. Æ Each carbon atom when singly-bonded has a _______________ geometry
Tetrahedral Geometry Simplified Drawing Geometry
C C
2
x Carbon atoms can form ____________ bonds with other carbon atoms! The end result is
C Æ C – C – C – C – C – C – C
(carb
lkanes – The simplest type of hydrocarbon
a chain of carbons known as a _______________________.
on atom) (carbon backbone) A
x Alkanes
: ____________________________________________________________
x They follow the general formula ____________ (eg. C2H6)
x All the bonds follow a ________________ arrangement, all the bonds form ____° angles
x They are very _______________ as C – C, and C – H bonds are strong and hard to break
x Short C1 to C4 chains are ________, C5 to C15 chains are _________, and long chains
with each other, and are _________ in length
such as C16 and above are __________ known as _____________________________.
riting the structure and formula for hydrocarbons
x There are 3 ways to represent a hydrocarbon formula
For example, propane (C3H8):
Æ Full structure
W
:
Æ Condensed structure
:
Æ Molecular Formula
:
Note
: Since each carbon atom is bonded to the maximum number of hydrogens available,
they are known as __________________ Hydrocarbons!
3
Naming Unbranched (Straight-Chained) Alkanes
ules: ber of carbon atoms in the carbon backbone. Use a prefix to denote the
Number of Carbons Prefix Used Number of Carbons Prefix Used
R
1. Count the numnumber of carbons.
1 6 2 7 3 8 4 9 5 10
2. Add the ending “______” to the prefix.
xample: CH4
= ________________
xample: C5H12
_ carbon atoms = ________________
aming Side Chains
Ex ___ carbon atom
Ex __
N
x ome hydrocarbon chains can have a side chain (or side group). These groups are known
CH3 – CH2 – CH – CH2 – CH2 – CH3 Å _____________________________
2 – CH3 Å ________________________________
x Alkyl Group
Sas __________ groups.
| CH
: ___________________________________________________________
x To name an alkyl group, use the ___________ for the number of carbon atoms and add
Eg. CH4 Æ – CH3 (one H removed = ______________ )
the ending “______”
4
Naming Branched Alkanes
ules: n of carbon atoms. This is the _________________!
. Identify all the side chains that branch off from the parent chain.
3. Number the carbon atoms on the parent chain consecutively starting from either the left
4. Starting with the first side chain in alphabetical order, name the carbon number the alkyl
5. If you have more than one of the same alkyl group, list each carbon number where the
The prefixes that you use are the following:
Number of times repeated Prefix Number of times repeated Prefix
R
1. Identify the longest continuous chai 2
side or the right side that gives the lowest possible set of numbers to the side chains
group is attached to, followed by a dash, and then the name of the alkyl group (eg. 2-methyl)
repeated group is attached, separated by commas, with a dash, and add the prefix to thealkyl group to show how many identical groups are attached. (eg. 2,3-dimethyl)
2 6 3 7 4 8 5 9
6. ame the parent hydrocarbon chain last
xample:
H3 – CH – CH2 – CH2 – CH3 Å parent chain = _______________
3 Å _____________ side chain on Carbon _____
_________________________
xample:
H3 – CH – CH2 – CH – CH2 – CH2 – CH2 – CH3
3 CH2 – CH3
__________________________________
N
E C | CH E
C | | CH _
5
Example:
CH2 – CH3
H – CH3
2 – CH3
________________________________________
tructural Isomers
| CH3 – CH2 – CH2 – CH – CH – C | | CH3 – CH2 CH S
ow that you know both branched and unbranched hydrocarbons exist, you will need to consider
onsider the following formula: C4H10
x The structure of this alkane can have the following possibilities:
or
ched
x Both of these structures have the same formula and are called ______________________
x Structural Isomers
Nthese types of structures when given a molecular formula. C
Straight-chained Bran
: _______________________________________________________
ycloalkanes – Cyclic Hydrocarbons
_______________________________________________________ _______________________________________________________ C
ydrocarbons don’t necessarily have to be in chains. They also exist in cyclic (ring) forms!
x Cycloalkanes have a general formula of ____________
We will primarily be dealing with 5 types of cycloalkanes:
Cyclopropane = C3H6 Cyclobutane = C4H8 Cyclopentane = C5H10
HThese types of hydrocarbons are known as ________________________.
x
6
Cyclohexane = C6H12 Cyclooctane = C8H16
Naming Substituted Cycloalkanes
Substitued cycloalkanes follow the same naming rule as branched alkanes except:
1. single substituent does not require a number to indicate the position of attachment. All
2. If more than one substituent is present, the first substituent is assumed to be at carbon
xample:
_______________________________
xample:
_______________________________
lkyl Halides – Halogen Side Groups
Acarbons are considered identical.
“1”, and the remaining substituents are numbered either clockwise or anticlockwise to have the lowest set of overall number values.
E E A
x Hydrocarbons can have halogens as side chains. These compounds are known as __.
x Alkyl halides have different reactivities depending on the type of halogen found.
Compounds with ____________ atoms tend to be the least reactive like Teflon, while compounds with ____________ atoms tend to be the most reactive.
__________________________. The halogens found are ____, ____, ____, and _
7
Most Reactive: I > Cl or Br > F Least Reactive:
g Alkyl Halides Namin
se compounds follow the same rules as branched alkanes except:
x The halo groups F, Cl, Br, and I are named as fluoro, chloro, bromo, and iodo
Exa
CH3 – CH – CH3
| F
_______________________
xample:
Br I | |
CH3 – CH – CH – CH – CH2 – CH3
____________________
The
respectively.
mple:
_____________ E | CH3 _________________
Chemistry 11 – Alkenes and Alkynes Notes
As you now know, alkanes are known as saturated hydrocarbons because they contain single-
bonded carbon atoms with the maximum number of hydrogens.
However, there are hydrocarbons that contain multiple-bonded carbon atoms. These are known as
_______________hydrocarbons because they have less hydrogen atoms when compared to
equivalent alkanes. We will investigate two types in this section: ___________and ___________.
Alkenes – Double-Bonded Carbon Atoms
x Alkenes: __________________________________________________________
x Double bonds can be found at the _______ or in the __________ of the carbon chain
x Alkene structure can be represented in two ways:
or
Naming Alkenes
Rules: The rules are similar to the Branched Alkanes except for the following:
1. Identify the longest continuous carbon chain that contains the double bond.
2. Change the ending for the parent chain to “______”
3. Number the parent chain so that the double bond gets the lowest possible number.
4. Use a number followed by a dash in front of the name of the parent chain to indicate
which carbon the double bond is bonded to. (eg. 2-butene) Example: CH
2 = CH – CH
2 – CH
3 Å _____________________________________
____________________
Example:
CH2 = C – CH
2 – CH
3 Å ________________________________
|
CH3 Å ____________________________
_________________________
Geometric Isomers in Alkenes – The Cis / Trans Thing When we were looking at alkanes, we found out that all the carbons were single-bonded. This
would allow for lots of flexibility in the bond and free rotation around each bond.
The arrows show the free rotation around the carbon atoms in propane.
However, if we look at alkenes, they contain a double bond in the carbon backbone. What does
that do to the geometry of those carbon atoms directly affected by the double bond?
x The tetrahedral shape of the carbon atom now becomes ______________________!
x The bond angle between the three atoms attached to the double-bonded carbon is _____°
x The double bond provides more strength to the molecule. It ____________ the affected
carbon atoms from ______________ around the double bond.
The rigid structure of alkene carbons has an important consequence: ____________________!
x Two requirements for __________________ isomers are:
1. A double bond
2. Groups (other than hydrogen atoms) which are attached to each of the carbons
involved in the double bond.
Example: 2-butene has two isomers possible
H3C CH
3 H
3C H
\ / \ /
C = C C = C
/ \ / \
H H H CH3
The two methyl groups are The two methyl groups are
on the same side of the on opposite sides of the
double bond. double bond.
____________________ ______________________
Alkynes – Triple-Bonded Carbon Atoms
x Alkynes: ____________________________________________________________
x Triple bonds can be found at the ______ or in the __________ of the carbon chain
x Alkyne structure can be represented in two ways:
or
Naming Alkynes
Rules: The rules are similar to the Alkenes except for the following:
1. Identify the longest continuous carbon chain that contains the triple bond.
2. Change the ending for the parent chain to “_______” Example: CH
3 – C Ł C – CH
3 Å ___________________________________________
____________________
Example:
HC Ł C – CH2 – CH – CH
3 Å ____________________________
|
CH3 Å __________________________
_________________________
Geometry of Alkynes
Alkynes contain a triple bond in the carbon backbone which is very rigid. It causes the carbons
affected to be “locked” to each other forming straight-line structures.
x The tetrahedral shape of the carbon atom now becomes _____________!
x The bond angle between the two atoms attached to the triple-bonded carbon is ______°
x The triple bond provides super strength to the molecule. It _________ the affected
carbon atoms and ____________ them from ______________ around the triple bond.
1
Chemistry 11 – Aromatic Compounds Study Guide
We have witnessed the existence of cyclic hydrocarbons in alkanes in the previous section. Is it also possible to have cyclic hydrocarbons for alkenes? The answer is absolutely _____! As you know, the carbons affected by the double bond will have its geometry altered. This would put a “______” in the ring structure causing some ________ or _________ in the cyclic hydrocarbon. Therefore, cycloalkenes are ____________________ structures than cycloalkanes.
Structure of Cyclohexane Structure of Cyclohexene However, there is one particular cyclohexene that is really stable. This ring structure, called ___________, has not one but _____________________ present. The three double bonds are found ______________ with the 3 single bonds in the structure. This unusual arrangement provides ________________ because the molecule undergoes _____________, where the double bonds can swap places with the single bonds continuously.
Resonance Structures of Benzene
2
Since benzene molecules can exist in ______ different resonance structures at any given time, benzene is frequently represented as follows:
The accurate representation The simplified representation of Benzene in structural diagrams Many large organic molecules actually contain one or more of these benzene rings. These molecules are known as ________________________.
x Aromatic Molecule: ____________________________________________________ The following are some common examples of aromatic molecules:
Naphthalene (C10H8) Benzo[a]pyrene (C20H12) _____________________________________ ____________________________________
3
Naming Substituted Benzenes Substituted Benzenes generally follow the same naming rules as ___________________. Example:
__________________________________ Example: __________________________________
1
Chemistry 11 – Functional Groups Notes
So far we have investigated hydrocarbon alkanes and have found that this particular group has
limited uses and properties. If all organic molecules were alkanes, then organic chemistry would
be useless and boring!
Luckily, ________________________________ are found on organic molecules, which give the
molecules more _____________________ and _____________________ with other compounds.
These groups of atoms are known as _______________________.
x Functional Group: ________________________________________________________
________________________________________________________
________________________________________________________
Functional groups may allow a molecule to:
x __________________________________
x __________________________________
x __________________________________
x __________________________________
x __________________________________
So far we have seen a couple of examples of functional groups present on hydrocarbons. They
are the carbon-carbon double bonds, carbon-carbon triple bonds, and halides. We will now
look at other important functional groups that are present in many everyday organic chemicals.
General Naming for Hydrocarbons Containing Functional Groups The following molecules containing functional groups will be named according to these general
rules:
1. Find the longest carbon chain containing the functional group. This chain determines the
parent name of the compound.
2. Change the ending of the parent name to the ending specific to the functional group.
3. Number the parent chain from the end nearest to the functional group so that the
functional group gets the lowest possible number. Place this number, along with a dash
in front of the parent name.
4. Identify the side chains, determine the carbon number that they are attached to, and
name them in alphabetical order.
2
Alcohols
x Alcohol: ________________________________________________________________
x They have a general formula of CnH2n+1OH Properties of Alcohols
x High boiling and melting points (due to _______________________ – the H from one
OH group interacts with the O from another OH group)
x All alcohols are poisonous, yes…even ethanol!
x They are ________ solvents (they have a specific positively charged end and a negatively
charged end)
x Alcohols have two opposing solubility tendencies due to their structure:
Æ The ________________ group tends to ______________ with water (which is
also a polar molecule) making the alcohol _____________
Æ The __________________________ tends to make alcohols _________ in water
Æ Therefore, short-chained alcohols tend to be more ___________ in water such as
methanol, ethanol, propanol, and butanol, while longer chains such as pentanol
and higher are _____________.
Naming Alcohols
x Use an ending of “_________” for the parent chain when naming alcohols
Example: CH3 – CH – CH2 – CH3 Å _________________________
| OH Å _________________________
__________________________
Example: CH3 – CH – CH2 – CH – CH2 – CH3 Å __________________________
| |
CH3 OH Å __________________________________
__________________________
3
Carboxylic Acids
x Carboxylic Acid: _________________________________________________________
_________________________________________________________
x The COOH group maybe shown as the following:
x They have a general formula of CnH2n+1COOH Properties of Carboxylic Acids
x High boiling and melting points due to hydrogen bonding
x They are polar molecules
x Can act as ________ (usually referred to as _____________________ ) Naming Carboxylic Acids
x Use an ending of “______________” for the parent chain when naming carboxylic acids (Note: the carbon in the COOH group is included in the parent chain!)
Example: CH3 – COOH Å _________________________________________________
_________________________________________________
________________________ (commonly called Acetic Acid – found in vinegar!)
Example: CH3 – CH2 – CH2 – COOH Å ______________________________________
______________________________________
_________________________ (the smell from smelly feet!)
4
Esters
x Ester: __________________________________________________________________
x The COO group maybe shown as the following:
x They have a general formula of CnH2n+2COO Properties of Esters
x They are good solvents (eg. Used in nail polish remover)
x Used to make ______________ (long-chained molecules); found in fats, oils, and waxes
x Pleasant smelling; often used in foods and other fragrances
Ester Odour Ester Odour Ethyl butanoate Pentyl propanoate
Pentyl ethanoate Ethyl methanoate
Octyl ethanoate Methyl butanoate
Naming Esters (Note the following exceptions:)
x Use an ending of “___________” for the parent chain when naming esters (Note: You can omit the position of the COO group in the naming of the parent chain)
x The hydrocarbon chain attached to the ________________ of the COO group is called
the _________________. The carbon in the COO group is also part of the parent chain!
x The hydrocarbon chain attached to the ________________ of the COO group is named
as an __________________. The name of this alkyl group exists as a
_________________ from the parent chain. Example:
CH3 – CH2 – COO – CH2 – CH3 Å _________________________________
-------------------
|
_____________________________
______________________________
5
Example:
CH3 – COO – CH2 – CH2 – CH3 Å _________________________________
----------
|
_____________________________
___________________________
Preparations of Esters
x Esters are made by reacting a _________________ with an ___________ in the presence
of an ____________________ such as HCl or H2SO4. This process is known as an
___________________ reaction.
x The following is an example of preparing methyl ethanoate from ethanoic acid and
methanol:
catalyst
Ethanoic acid Methanol Æ Methyl ethanoate Water
O O
|| H+ ||
CH3 – C – O – H + HO – CH3 Æ CH3 – C – O – CH3 + H2O
The H from the acid and the OH from Ethanoic acid loses an H to become
the alcohol are removed to form H2O. “ethanoate” in the ester. Methanol
loses OH, to become a “methyl” group
in the ester.
Try to name the products and draw the esterification reaction for each test tube in Lab 23B.
Aldehydes
x Aldehyde: ______________________________________________________________ ______________________________________________________________
x The CHO group maybe shown as the following:
x They have a general formula of CnH2nO
6
Properties of Aldehydes
x Generally soluble in water due to hydrogen bonding
x Common aldehydes are liquids
x Distinctive odours (generally pleasant!) Naming Aldehydes
x Use an ending of “_______” for the parent chain when naming aldehydes (Note: the carbon in the CHO group is included in the parent chain!)
x Since the CHO group is found on the ______ of a hydrocarbon chain, the _____________
of the CHO group can be ____________ from the parent chain name. Example:
O
|| H – C – H
_________________ (commonly called Formaldehyde – Used as a preservative in
biological specimens)
Example:
O
|| CH3 – CH2 – CH – C – H Å _______________________________
|
CH3 Å ______________________________
________________________
7
Amides
x Amide: _________________________________________________________________ _________________________________________________________________
x The CONH2 group maybe shown as the following:
x They have a general formula of CnH2n+1CONH2
Properties of Amides
x Polar molecules and good solvents
x The amide group forms the backbone of all protein molecules (links individual amino acid
subunits together)
x Can be used to form synthetic polymers Naming Amides
x Use an ending of “____________” for the parent chain when naming amides (Note: the carbon in the CONH2 group is included in the parent chain!)
x Since the CONH2 group is found on the end of a hydrocarbon chain, the position of the
CONH2 group can be omitted from the parent chain name.
Example:
CH3 – CONH2
________________________
Example:
O
|| CH3 – CH – CH2 – C – NH2 Å ________________________________
|
CH3 Å ________________________________
_________________________
8
Ketones
x Ketone: ________________________________________________________________ ________________________________________________________________
x The CO group maybe shown as the following:
x They have a general formula of CnH2nO (same as aldehydes)
Properties of Ketones
x Similar properties as Aldehydes
Naming Ketones
x Use an ending of “_________” for the parent chain when naming ketones
(Note: the carbon in the CO group is included in the parent chain!) Example:
O
||
CH3 – C – CH3 Å ________________________________________________
______________________ (known as Acetone – common ingredient in nail
polish remover)
Example:
O
|| CH3 – C – CH2 – CH – CH3 Å ______________________________________
|
CH3 Å __________________________
___________________________________
9
Amines
x Amine: ________________________________________________________________
x They have a general formula of CnH2n+1NH2
Properties of Amines
x They are ____________________ and react with acids
x Smelly compounds (tend to have a fish-like odour)
Naming Amines
x Use an ending of “____________________” for the parent chain when naming amines
Example:
CH3 – CH2 – CH2 – NH2 Å ________________________________________
__________________________
Example:
CH3 – CH – CH2 – CH2 – NH2 Å ___________________________________
|
CH3 Å ______________________________
___________________________
Ethers
x Ether: __________________________________________________________________
x The oxygen atom maybe shown as the following:
x They have a general formula of CnH2n+2O
10
Properties of Ethers
x Tend to be quite ___________________ molecules
x Good solvents
x Some ethers (eg. Diethyl ether) are used as an _____________________ in hospitals on
people and by biologists on animals and insects Naming Ethers (Note the following exceptions:)
x Consider the _______________ atom in the ether group to be the __________________
and use the name “__________”
x Treat the _____ hydrocarbon chains attached to the oxygen atom as _________________
and name them in alphabetical order with ___________ in between each side chain. Example:
CH3 – O – CH2 – CH3 Å _______________________________
___________________________
Example:
CH3 – O – CH3 Å ______________________________
___________________________
In Organic Chemistry, you will come across molecules that contain more than one type of
functional groups. In that case, you will have to determine which functional group has the
highest priority in naming by using a functional groups naming chart. You will not be
expected to do this in Chemistry 11 but for future reference, the following chart is provided.
11
Chemistry 11 – Functional Groups Naming Chart
Highest Priority
Functional Group
Formula General Equation
Example Nomenclature
Carboxylic
Acid
O
||
– C – OH
CnH2n+1COOH
O
||
CH3-CH2-C-OH
Propanoic acid
- anoic acid
(pos. # not rqd!)
Ester
O
||
– C – O –
CnH2n+2COO
O
||
CH3-CH2-C-O-CH3
Methyl propanoate
- anoate (alkyl group on
oxygen atom)
Amide
O
||
– C – NH2
CnH2n+1CONH2
O
||
CH3-CH2-C-NH2
Propanamide
- anamide
(pos. # not rqd!)
Aldehyde
O
||
– C – H
CnH2nO
O
||
CH3-CH2-C-H
Propanal
- anal
(pos. # not rqd!)
Ketone
O
||
– C –
CnH2nO
O
||
CH3-CH2-C-CH2-CH3
3-pentanone
- anone
Alcohol
– OH
CnH2n+1OH
CH3-CH2-CH2-OH
1-propanol
- anol
Amine
– NH2
CnH2n+1NH2
CH3-CH2-CH2-NH2
1-propanamine
- anamine
Ether
– O –
CnH2n+2O
CH3-O-CH2-CH3
Ethyl methyl ether
- ether (alkyl alkyl ether)
Alkene
C = C
CnH2n
CH2=CH-CH2-CH3
1-butene
- ene [cis/trans isomers]
Alkyne
C Ł C
CnH2n–2
CHŁC-CH2-CH3
1-butyne
- yne
Alkane &
Alkyl
Halides
C – C
F,Cl,Br,I
CnH2n+2
CH3-CH2-CH2-Cl
1-chloropropane
- ane
Lowest Priority