Upload
shiuman-lim
View
153
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Organic chemistry chapter 1
Citation preview
We knew, the word organ have close relationship with the word Organism
Have you ever come across the word organ/organism …….?
The basic word for organic came from the word organ
Where is the word of organic came from ………?
The study the compound of these elements
Therefore, organic chemistry is the study chemistry of carbon compounds, but also it also included the compounds containing, hydrogen, oxygen, nitrogen, and other elements such, halogen, phosphrous and sulphur, as shown in the following periodic table;
Examples Of Organic Compounds:
Compounsd Formula Elements Present
Benzene C6H6 C, H Vinegar CH3COOH C, H, O Sucrose C12H22O11 C, H, O Chloroform CHCl3 C, H, Cl Urea CO(NH2) C, H, O, N Protein(alanine) C3H7O2N C, H, O, N
Can any one in class explain what are some of the uses of the above compounds …….. ?
Before we discuss futher about the chemical bond, we should know of the following concept: 1. electronic configuration of an elements 2. Octet configuration
1H
2He
e
ee
3Li
4Be
5B
6C
8O
e
e
e
1
2
2,1
e
e
ee
2,2e
e ee
e2,3
e
e
ee
e
e
2,42.6
ee
e
e
ee
ee
e
2s,2p1s
11Na 2,8,1
What is the electronic configuration meant….?
A particular arrangement of electron in the orbitals of an atom
J.McMurry p. 4
1H = 1S1 =
2He = 1S2 =
3Li = 1s22S1 =
4Be = 1s22S2 =
5B = 1s22S22p1 =
6C =1s22S22p2 =
7N =1s22S22p3 =
8O =1s22S22p4 =
9F =1s22S22p5 =
10Ne=1s22S22p6=
1S 2S 2p (pxpypz)
2.8 Octet
J.McMurry p. 5
1. Aluminium2. Cromium3. Manganese4. Copper
Write the configuration of the following elements
13Al = 1s2 2s2 2p6 3s2 3p1
24Cr = 1s2 2s2 2p6 3s2 3p6 4s13d5 ( x 4s2 3d4 )25Mn = 1s2 2s2 2p6 3s2 3p6 4s23d5
29Cu = 1s2 2s2 2p6 3s2 3p6 4s13d10 ( x 4s2 3d9 )
2 Filled > 2 half- filled > 1 filled 1 not half
Reaction between AB + C == > D Take place. Why ……. ?
The Chemical reaction take place inorder the system becomes:
1. More order …. ?2. More stable …. ?
AB + C
---------
AC + B
---------------E
ener
gy L
evel
Reaction Coordinate
H reaction
Atom at distance
Atom Bonded In Molecule
Energy
Ikatan Perkahwinan Menjadikan Individu Lebih Tenang/Stabil/Tersusun
Antara lelaki/perempuan
Antara lelaki/lelaki Antara Perempuan/perempuan
Stronger bonded
Weaker bonded
Covalent
Ionic/Heterovalent
1. Sharing electron among the elements ( covalent )2. Give/received the electron(s) == > ions3. Attraction between different ions ( ionic )4. Restructuring the electronic configuration in the
molecules Breaking down the bonds = (required energy) Rearrangement the pair(s) of electron(s)/Bonding Formation of new bonds (released energy)
A + A == > B (H+H ==> H2)AB+C == > A–C + B (H2+½ O2== > H2O)
Base on your experiences, can you name the types of bonding in chemistry ?.
There are:
1. Ionic bonding
2. Covalent bonding
3. Metallic bonding
4. Hydrogen bonding
By transfering/receiving an electron of electropositive and electronegative atoms
How does the ionic bond formed …..…. ?
Can any one in class explain it.. …………?
Electropositive element, (Na) gives up one valence electron, to have octet configuration and form a positive charge
Example Na (electropositive) and F (electronegative)
What is the configuration electron of Na atom ……?
11Na =
10Na+ = Octet Configuration “Stable”
J.McMurry m.s 7
Electronegatif element, (F) received one valence electron, to have octet configuration and form a negative charge
What is the configuration electron of F atom ? 9F =
10F- = Octet Configuration “Stable”
Na+ Na --- F F-
Electrostatic attraction Ionic bond
Ionic compound
Different charge Of (Na+) and (F-) attract together by electrostatic force to form ionic bond
Electropositive element Electronegative element ( Na ) 2.8.1 F ( 2.7 )
Give up 1 electron receive 1 electron
Na+ 2.8 (Octet/stable) Cl- ( 2.8 ) (octet/stable)
Different charge
Electrostatic force
Na --- F (Ionic Bonding
J.McMurry, p11
The word covalent is made up of two basic words, What are they …..?
They are CO + Valent ( valence )
What is the meaning of Co and valence ….. ?
Co meant sharing and valence related to valence electron
What is the meaning covalent bond than ….. ?
Bond formed by sharing of valence electron by any atoms so that each one atom to achieved an octet stable configuration ( Configuration od noble gas)
Example:
.. ..: F: : F : .. ..
F -- F
..H : O : H ..
H -- O -- H
..O :: C:: O ..
O = C = O
Electronic configuration for F = 1s2 2s2 2p5 Less one electron
J.McMurry, p11
Electronic configuration for Ne (noble gas) = 1s2 2s2 2p5
F atom would share one electron to another F atom to achived, octet (stable)configuration and form a covalent bond:
.. : F .
..
.. . F :
..
.. ..: F: : F :
.. ..
F – F
Covalent Bond
Sharing electron
There are two types of covalent bonds; i) Sigma () bond ii) Pi ( ) bond
Is a covalent bond formed by orbitals overleapping end to end of the following orbitals:
i) two s orbitals ii) 1 s orbital and 1 p orbital iii) 2 p orbitals ( head-head or end-end )
What do you understand by sigma () bond………?
Its electron density is concentrated between the nuclei of the bonding atoms.
Study the following diagrams given
J.McMurry, p11
+
+
+
bond
bond
bond
S orbital S orbital
S orbital p orbital
p orbitalp orbital
Electron density
Head-to head overleap Atomic Nucleous
bond
bond
bond
Electron density
Does any one can explain what is pi () bond meant.…?
pi () bond is a covalen bond formed by overleapping of side-by-side of P orbitals.
Its electron density is concentrated above and below the plane of the nuclei of the bonding
Exame the following diagrams:
J.McMurry, p17
pz Orbital
px Orbital
py Orbital
bond
bond
bond
Side by side overleap
Electron density
Electron Density
Draw the structure of 2-methyl-2-butene and identify the sigma () and pi () bond in the molecule
Also known as electron dot structure
A concept to show the structure of a molecule by using dots and dashes to show the valence electrons and shared pairs of the electrons
J.Mcmurry p, 8-9
Have you ever heard the terms “Lewis Structure” …. ?
Can any one give an example of a lewis Have you ever heard the terms “Lewis Structure” …. ?
Example: Hydrogen atom have 1 valence electrons. What is the lewis structure of carbon
Example: carbon atom have 4 valence electrons. What is the lewis structure of
carbon .. C . .
Example: one molecule of water was formed as result the combination
between 2 atoms of H and one atom of oxygen. H atom has 1 valence electron and oxygen have 6 valence eklectrons.
Can any one write the chemical and lewis structure of the above statement ?.
H2 + ½ o2 H2O
.. ..2H. + . O . H- O - H .. ..
Can any in class write the lewis structure of NH3?How many valence electron N have ……?
N have 5 valence electrons
. : N . .
Can any in class write valence electronic for N … ?
Now, Can any in class, write the lewis structure of NH3 H :
: N : H : H
or H I : N -– H I H
Please, write the lewis structure of the following molecules/compounds
i) Common salt
ii) Chloroform
iii) Ethanol
iv) Vinegar
What is the meaning of polar covalent bond …….?
What is/are the factors that determine covalent bond become a polar bond… ?
A bond in which electrons are not shared evenly (the density of the electron is not evenly distributed through the molecule and hence is a polar molecule
The electronegativity of the elements that form the covalent bond/molecule
Majority of the molecules are not 100% ionic nor 100% covalent
The molecules which not 100% ionic ( fully charge) or 100% covalent (electronically symmetrical) are called polar molecule (partially charge)
Example: Electrons are located more on F atom rather than in H ;Hel < Fel Hence at F is more negatif charge and at H is more positive charge; ..
H --- F : ..
When a covalent molecule formed between two different element having different electronegativity, such as:
H (2.1) and F ( 4.0)
the density of electron in both end of the molecules are not even. As result the polarity both end are different.
Different element have different electrogenativity, Example:
• Element Electronegativity
• H 2.1• Li 1.0
• Be 1.5• B 2.0
• C 2.5• N 3.0• O 3.5• F 4.0
Element Electronegativity Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0
The end with higher density of electron will be negative charge and the other end will positive charge
Or H ------ F ..H --- F : ..
+ -
The symbol + indicate partially (+) charge and - indicate partial (-) charge
The symbol --- > indicate the direction of polarization
If a molecules formed of different element hqaving different electronegativity the molecules should be polar.
Example
O-O, C-C, ( Less/not polar )
C- H, C- Cl, N - F, O-H, O-Cl ( polar )
At end of this disussion students should be able to:1. Define what hybridization is …. ?2. Explain how the formation of hybridization sp3 in
carbon3. Explain how the formation of hybridization sp2 in
carbon4. Explain how the formation of hybridization sp in
carbon
What do you meant by hybridization…… ?
Example: s orbital mix with 1 p orbital == > sp orbital
The mixing of different types of atomic orbital to produce a set of equivalent hybride orbital
J.Mcmurry p 12
+
s p sp
• There are 3 types of hybridization can occur in carbon:
• 1. Sp3 hybridization • 2. Sp2 hybridization• 3. Sp hybridization
What is the normal valence electrons of carbon in organic compounds?
Can you write the electronic configuration of carbon atom..?
What is the atomic number of carbon? six
1S2 2S2
2,4
or
2px2 2py 2pz
How many unpaired valence electron in the configuration available for bonding formation? Two (2)
four (4)
J.Mcmurry p 14
When carbon atoms, received enough energy, one electron from 2s orbital will move (jump) to 2py orbital, as shown, below:
How does the configuration electrons in carbon should change, inorder their valence electron becomes 4?
One of the electron from 2s orbital should move to py orbital
How?....
1s 2s 2px 2py 2pz
And now their electronic configuration becomes :
**Excited
How many unpaired electron available for formation bonding now that carbon atom have?
What is the angle between axis Px, Py and Pz90 o
py
px
pz
Can any one of you draw the axis of p orbital ? How does its look like ?
1s 2s 2px 2py 2pz
1s orbital + 3 orbital p == > Hybride == > Sp3 orbital
If carbon atom using 3p atomic orbital for bonding, what should be the angle of the bonding? ……
90o
Do you agree that most compouds involving carbon atom has bond angle of 90o? ….. What is your comman? ………
No
What is actually happen to the 4 unpaired electrons in carbon atom ? ………..
All four unpaired electrons are mix/combine together to form new 4 orbitals which equivalent each other
The process of transfer electron from s -- > p followed by the combine of four orbital to form special 4 equivalent orbital is known as Hybridization
The sp3 have following shape?
If not 90o, what should be the shape of the new orbital..?
= >sp3
The original S and p characteristic lose it identity
New identity orbitals is 4 new equilvalence orbital
special characteristic
Equivalent in angle,
Equivalent in bond strength
**Excited
s 3 pSp3 (tetrahedral)
H H HH
C ( sp3)Methane ( CH4 )
The 4 unpaired electron will shared by one electron each from hydrogen atom to form CH4
J.Mcmurry, p 18
As mentioned before, After 1 el (2s) move to 2p the electronic configuration in carbon atom becomes :
**Excited
1s orbital and 2 p orbital will hybrid each other to form sp2 hybrid;
How does the sp2 hybrid in carbon is form?
sp2
Can any one in class proposed … How the formation of Sp2 hybridization in carbon ? ……
1s 2s 2px 2py 2pz
J.Mcmurry p 16
Example:H2C=CH2
C sp2
C sp2
Overleaping 2 (C sp2)
bond
bond
or
Sp2 Sp2
or
Overleaping of 2 (Csp2)
H2C=CH2
As mentioned before, After 1 el (2s) move to 2p the electronic configuration in carbon atom becomes :
**Excited
1s orbital and 1 p orbital will hybrid each other to form sp hybrid;
How does the sp hybrid in carbon is form …..?
Can any one in class proposed … How the formation of sp hybridization in carbon ? ……
1s 2s 2px 2py 2pz
**Excited
1s 2s 2px 2py 2pz
sp
Discuss the formation of hybridization in: i) NH3
ii) H2O
iii) BeCl2
• At end of this disussion students should be able to:
• 1. Discuss how a bond is beeing broken • 2. Discuss homolytic, heterolytic, nucleophile,
electrophile, carbocation and carboanion.• 3. Explain define distillation• 4. Explain the differences of simple distillation and
fractional distillation
In the chemical reaction the covalent bond beak by two ways:
i) Homolytic ii) Heterolytic
How does a covalent bond breaking in the chemical reaction…. ?
Let we discuss each types in relatively detail
A ¦ B === > A• + B• (Free radical)
So homolytic mean, a bond that break in an electronically symmetrical way, I.e:
It meant, one electron remains with each product fragment to form a free radical species, as shown below
What is the homolytic meant … ?
homolytic made up of homo (same) and lytic (loosing)… ?
What is the free radical ? Can any one give the definition of a radical .. ?
Radical is a species which have unpaired electron …..
Example:
CH4 == > CH3• + H • H H .. .. H : C : H ==> H :C. + H. .. .. H H
it is a reactive species
Radical is sp2 hybridized and planar
The orbital of radical is not empaty but it containsthe odd electron
So heterolytic is bond break down in an electronically unsymmetrical way
It meant that both electrons remain with one product fragment, living the other one with a vacant orbital
This process produced of a pair of ions, i.e; (cation and anion )
Can any one in class suggested the mechanism involved….?
What is the heterolytic meant … ?
heterolytic made up of hetero (different/not same) and lytic (loosing)… ?
A : B === > A+ + :B ( A: + B+ ) Ion ( cation/anion )
+ -
R – C -->-- X === > R– C + + X-
(Carbocation)/C’anion ( anion )
The mechanism of breaking down of the bond are given below:
If the process invloved carbon ( alkyl group ) a carbocation/carboanion is produce, as shown below:
Example: CH3 .. CH3
CH3 – C ---- Cl : === > CH3– C + + Cl-
CH3 .. CH3 (Carbocation) ( anion )
• - +• R – C --<-- MX === > R– C- + MX+
• (Carboanion) ( anion )
Example
• + -• (CH3)3– C : Cl === > (CH3)3– C+ + Cl-
• (Carbocation) ( anion )
Carbocation is also known as carbonium ion
What is carbonium ion…. ?
Carbonium ion is a species that contain a carbon atom bearing a positive charge
The (+) charge carbon atom is bonded to other atoms and it has no non-bonding electron.
It is sp2 hybridized with a planar structure and bond angles of about 120o
The unhybridized p orbital is vacant and lies perpendicular to the plane of the C-H bonds
Has only six electrons in its valence shell
At end of this discussion students should be able to:1. Define what is the carboanion 2. Define and give example of eletrophile and
nucleophile 3. State the differences of nucleo/electro phile4. Explain define distillation5. Explain the differences of simple distillation and
fractional distillation
Carboanion has a trivalent carbon atom that bears a (-) ve chargeThere are 8 electrons around the carbon atom ( 3 bonds and one lone pair )
It is a rich electronsIt is strong nucleophile ( lewis base )
The carbon atom is sp3 hybridized and tetrahedral in shape
One of the tetrahedral positions is occuoied by an unshared lone pair of electrons
What is the Carboanion ……?
Electron-deficient compounds have tendency to undergo chemical reaction inorder to complete their valence electron becomes octet. How … ?
Electron-deficient compound will react with a species (compound) that has one or more unshared valence electron pairs
Can any one give the example …. ? .. :F: F .. I .. :F -- B + [ : F ; ]- == > F – B -- F .. I .. I : F : F ..
In above reaction, the electron dedficient compound acts as a Lewis acid ( Electron acceptor )
The species that provides the electron pair act as Lewis bes. ( Electron donor )
In organic the lewis acid terms known as an electrophile and lewis bes known as nucleophile
.. :F: F .. I .. :F -- B + [ : F ; ]- == > F – B -- F .. I .. I : F : F ..
Lewis acid (electrophile)
Lewis bes (nucleophile)
What is electrophile meant .. ?
Electrophile made up of two words
( Electro + phile )
Electro mean is related with electron
Phile mean lovingLoving electron
What is nucleophile meant .. ?
Nucleophile made up of two words
( Nucleo + phile )
Nucleo mean is related with nuclei
Phile mean lovingLoving nuclei
H F H F
H N : + B F === > H N B F
H F H F
Nucleophile electrophile
.. H .. HCH3 – O : + H C Cl === > CH3 O C H + Cl-
.. H .. H Nucleophile electrophile
What do you understand of fractional distillation ……?
What do you meant of distillation ….?A process to separate a liquid mixture ( from liquid/ liquid) by boiling of the mixture in distilation apparatus.
G.I Brown, p 56
Fractional distillation is a procedure for separating liquid components of a solution that based on their different boiling points
2. Heating Mentel3. Flask
4. Fractionating column5. Condenser
6. Collection Bottle
1. Sampel
Sections Of Apparatus
Simple Distillation Fractional Distillation
Can you list out the differences between these two proceses…?
Gases B.P < 20oC, (C1-C4) hydrocarbon, used fuels & reactants to make plastics
Gasoline(napthas) 20-200oC (C5-C12) hydrocarbon, Used as motor fuels & Industrial solvents
Karosene 175-275oC (C12-C16) hydrocarbon, Used for lamp oil, diesel starting material for catalytic cracking,
Fuel oil 250-400oC (C15-C18) hydrocarbon, Used for catalytic cracking, heating oil, diesel fuel)
Lubricating oil < 350oC (C15-C20) hydrocarbon, Used as lubricatants),
Residue (asphalt) (>C20 hydrocarbon)
The more volatile fraction which consist of smaller molecules, are received from higher up the columm
Less volatile factions from lower columm
Fraction Temp oC No Of Carbon UseResidue >400 25 Heavy fuel oil & Butumen
Heavy Gas-oil light. 300-400 18-25 Fuel.Lubrication. Paraffin
Light Lubrication oil 300-400 Medicinal paraffin
Light gas-oil 250-300 13-17 Fuel oil Diesel enginers
Kerosine 190-250 11-14 Fuel oil (paraffin oil) Trctor & Jet-engines
Naphtha 100-200 Solvent & Raw material
Petrol (gasoline) 40-180 5-10 Fuel
Petroleum ether 40-60 Solvent 60-80
Gas Fraction < 40 1-5 Gaseous Fuel Source of Alkanes
G.I Brown, p 83-85
You are given a mixture containing C2H6, C10H22, C40H80. …Discuss how the mixture can be saperated ?
•Organic CompoundsHydrocarbon
Saturated Unsaturated
Straight Chain Cyclo Chain
Aromatic
Derivatives Of Hydrocarbon
Alkyl halides
Acid Halides
Ethers
Alcohols Aldehydes
Ketones Carboxylic Acids
amines
AcidamidesNitrilesAcid
Anhydrides
esters
(Aliphatic & Aromatic)
What is the functional group ……?
An atom (or group of atoms) that is part of a larger molecules and has a characteristic chemical reactivity.
The examples of functional group are given in the following table:
The functional group determine the chemical properties of the compound.
Compounds Fungsional gp G.Formula Example Alhyl Halide, Halogen RX CH3ClEther, -O- ROR CH3OCH3
Alcohol, -OH ROH CH3OHAldehyde, -CHO RCHO CH3CHOKetone, - CO - R-CO-R CH3COCH3
Carboxyalic acid, - COOH RCOOH CH3COOHEster - COO RCOOR CH3COOCH3
Amine, - NH2 RNH2 CH3 NH2
Amide -CONH2 RCONH2 CH3CONH2
Type Of Glass Composition (mass) Properties & Uses
Pure Quartz Glass 100 % SiO2 Low thermal expansion, Transparent (Optical research)
Pyrex Glass 60-80% SiO2, 10-25% B2O3, Littke Al2O3 Low thermal expansion, Transparent ( Lab Ware, House hold ware )
Soda-lime 12% Na2O, 12% CaO, 76% SIO2 Attck by chemical, Transparent, Sensitive to thermal shock ( Windo glass, Bottles)
Aluminosilicate 5% B2O3, 10% MgO, 10% CaO High Melting, (Cooking ware) 20% Al2O3, 55%SiO2
Lead alkali 10% Na2O, 20%PbO, 70% SIO2 High refractive index; (Lenses, Decorative glass)
Borosilicate 5% Na2O, 3% CaO, 16% B2O3, Low Coefficient of thermal expension; 76% SiO2 (Laboratory ware, cooking utensils
Bioglass 24% Na2O, 24% CaO, 6% P2O5, Compatible with bone,( Coating 46% SiO2 on srgical implants
R.Chang, p 460-462
Type Of Glass Composition (mass) Properties & Uses
Pure Quartz Glass 100 % SiO2 Low thermal expansion, Transparent (Optical research)
Pyrex Glass 60-80% SiO2, 10-25% B2O3, Littke Al2O3 Low thermal expansion, Transparent ( Lab Ware, House hold ware )
Soda-lime 12% Na2O, 12% CaO, 76% SIO2 Attck by chemical, Transparent, Sensitive to thermal shock ( Windo glass, Bottles)
Aluminosilicate 5% B2O3, 10% MgO, 10% CaO High Melting, (Cooking ware) 20% Al2O3, 55%SiO2
Lead alkali 10% Na2O, 20%PbO, 70% SIO2 High refractive index; (Lenses, Decorative glass)
Borosilicate 5% Na2O, 3% CaO, 16% B2O3, Low Coefficient of thermal expension; 76% SiO2 (Laboratory ware, cooking utensils
Bioglass 24% Na2O, 24% CaO, 6% P2O5, Compatible with bone,( Coating 46% SiO2 on srgical implants
R.Chang, p 460-462
Type Of Glass Composition (mass) Properties & Uses
Pure Quartz Glass 100 % SiO2 Low thermal expansion, Transparent (Optical research)
Pyrex Glass 60-80% SiO2, 10-25% B2O3, Littke Al2O3 Low thermal expansion, Transparent ( Lab Ware, House hold ware )
Soda-lime 12% Na2O, 12% CaO, 76% SIO2 Attck by chemical, Transparent, Sensitive to thermal shock ( Windo glass, Bottles)
Aluminosilicate 5% B2O3, 10% MgO, 10% CaO High Melting, (Cooking ware) 20% Al2O3, 55%SiO2
Lead alkali 10% Na2O, 20%PbO, 70% SIO2 High refractive index; (Lenses, Decorative glass)
Borosilicate 5% Na2O, 3% CaO, 16% B2O3, Low Coefficient of thermal expension; 76% SiO2 (Laboratory ware, cooking utensils
Bioglass 24% Na2O, 24% CaO, 6% P2O5, Compatible with bone,( Coating 46% SiO2 on srgical implants
R.Chang, p 460-462