organicchemistry-firoz rathor-XI-A

Chemistry project workby-firoz rathor class-XI-A : 

Chemistry project workby-firoz rathor class-XI-A

ORGANIC CHEMISTRY : 

ORGANIC CHEMISTRY Organic chemistry is the study of carbon containing compounds derived from living organisms. Oil is formed over millions of years from the break down of dead creatures and plants. 80+ million compounds- natural & synthetic. Crude Oil (petroleum) is a mixture of many thousands of these different compounds and is the main source of many of these chemicals. They are called hydrocarbons because they predominantly contain the elements hydrogen and carbon.

Distillation of Crude Oil : 

Distillation of Crude Oil

Slide 4: 

Homologous series This is a series of compounds which all contain the same functional group, and have similar chemical properties.  ALKANES ALKENES ALCOHOLS CH4 CH2 =CH2 CH3OH CH3-CH3 CH2 =CH –CH3 CH3CH2OH Each has a general formula: ALKANES: CnH2n+2 The members of the series differ by the number of CH2 units. CH3-CH3, CH3-CH2-CH3, CH3-CH2-CH2-CH3 Graduation in physical properties:  eg: boiling points. CH4 (GAS), C8H18 (LIQUID), C30H62 (SOLID)

ALKANES : 

ALKANES SATURATED HYDROCARBONS – contain maximum amount of hydrogen - only single bonds (no multiple bonds) GENERAL FORMULA CnH(2n+2) NAMING ALKANES All alkanes end with ‘ANE’. All belong to the same HOMOLOGOUS series

Slide 6: 

Functional groups The functional groups are atoms or combinations of atoms which determine the properties of organic molecules.

STRUCTURES OF ALKANES : 

STRUCTURES OF ALKANES METHANE CH4 Bond Angle 109.5o Shape Tetrahedral Can be illustrated as:

ETHANE. : 

ETHANE. Molecular formula C2H6

PROPANE. : 

PROPANE. Molecular formula: C3H8 Both ethane and propane are “straight” chain molecules BUT!! Bonds are NOT 90o molecules are NOT STRAIGHT!!! Schematic formula

Slide 10: 

Molecular formula: C4H10 - can have two different structures BUTANE Branched chain CH3 CH CH3 CH3 METHYL PROPANE Isomers Compounds that have the same molecular formula but different structural formula. branch BUTANE & ISOMERS. Schematic formula:

Names & Structures of three different isomers C5H12. : 

Names & Structures of three different isomers C5H12. Examples 2- methylbutane 2,2 – dimethyl propane CH3CH(CH3)CH2CH2CH3 CH3CH(CH3)CH(CH3)CH3 CH3C(CH3)2CH(CH3)CH2CH3

Slide 12: 

THE RULES FOR NAMING ORGANIC COMPOUNDS Choose the longest unbroken chain of Carbon atoms and assign a name for the carbon chain using the prefixes; meth-1, eth-2 etc. Identify any carbon chain branches (alkyl groups). These are assigned names using the same prefixes as above along with the suffix “-yl” – methyl, ethyl etc. Identify the functional groups present in the molecule. Assign a prefix or suffix according to their homologous series. These will be written in front of the name of the carbon chain. There is an order of precedence, to decide the suffix for the carbon chain: COOH / C=C > OH > Br / Cl Number the Carbon atoms in the longest chain so that the branches/functional groups have the lowest number possible. Allocate a number for every group/branch no matter how many times it occurs. Where groups are on the same carbon write their names in alphabetical order. Numbering takes precedence "wins" over alphabetical spelling. Prefixes are used for groups that occur more than once. Di – 2 Tri – 3 Tetra – 4 Penta – 5 etc. The final name is written as one word with commas between numbers, hyphens separating numbers from words.

Slide 13: 

Give the names of the following alkanes 3-methyl pentane 2,4-dimethylpentane 2,2,4-trimethyl hexane 2,2,3-trimethylpentane

Cyclic Alkanes : 

Cyclic Alkanes When C atoms bond together to form a ‘ring’ – known as a ‘cyclic’ structure. What is the molecular formula of this alkane? How does the molecular formula compare to the general formula for alkanes? Why does it belong to the series of alkanes? Illustrate the cyclic structures of (a) C4H8 and (b) C5H10 and name the molecules. CYCLOHEXANE Can you think of a name for this molecule

Slide 15: 

The shape around the double bond is planar. The bond angle around the double bond is 120o Structure of Alkenes

Examples of Alkenes : 

Examples of Alkenes ETHENE, C2H4 TASK: Use ball & stick models or sketches to construct and name 3 different structures for C4H8 each one with one double bond. BUT-1-ENE BUT-2-ENE METHYL PROPENE

More Alkenes : 

More Alkenes Illustrate structures of the following alkenes: Pent-1-ene Hex-3-ene 2-methylbut-1-ene Cyclohexene Name the following alkenes Pent-2-ene 3-methylpent-1-ene 2-methylhex-3-ene 2,4,4-trimethylpent-2-ene

GEOMETRIC ISOMERS : 

GEOMETRIC ISOMERS There is no rotation about the double bond. Geometric isomerism is a form of STEREOISOMERISM – Same molecular and structural formula but atoms are arranged differently in space GEOMETRIC ISOMERISM each C atom in the double bond has two different atoms/groups attached. cis but-2-ene trans but-2-ene

Alkynes : 

Alkynes H-C≡C-H H-C≡C-CH3 H-C≡C-CH2-CH3 CH3-C≡C-CH3 Ethyne propyne But–1-yne But–2-yne Very reactive Triple bond unstable! Attracts electrophiles.

Slide 20: 

General formula CnH(2n+1)X HALOALKANES Substituted alkane with at least one halogen atom Structures & Names CH3Cl chloromethane CH3–CH2 –CH2Br 1- bromopropane 2- iodobutane

Slide 21: 

Primary, Secondary & Tertiary Haloalkanes CH3–CH2–CH2–CH2Br PRIMARY 10 SECONDARY 20 2-bromobutane TERTIARY 30 2-bromo-2-methylbutane 1- bromobutane

Slide 22: 

ALCOHOLS General formula CnH(2n+1)OH CH3OH Methanol CH3CH2OH Ethanol C3H7OH – two isomers CH3—CH2—CH2OH Propan-1-ol 1o TASK: C4H9OH has 4 isomers. Draw the structures of each isomer giving the name and class of each one. Hydroxyl group

Slide 23: 

MANUFACTURE OF ETHANOL FERMENTATION – sugars (glucose)/yeast/25oC – 35OC HYDRATION OF ETHENE Renewable sources Low energy Cheap Batch Slow Impure/Low yield Fast Pure High yield /continuous High energy Non-renewable Expensive

Slide 24: 

ALDEHYDES & KETONES KNOWN AS CARBONYLS STRUCTURE ALDEHYDES GENERAL STRUCTURE EXAMPLES HCHO - methanal CH3CHO - ethanal CH3CH2CHO - NAME? Illustrate the structures of these examples

Slide 25: 

KETONES GENERAL FORMULA R and R1 may be the same or different EXAMPLES CH3COCH3 propanone CH3COCH2CH3 butanone CH3CH2COCH2CH3 pentan-3-one Illustrate the structures of these examples – show & name the corresponding aldehyde isomer. NOTE: ALDEHYDES & KETONES EXHIBIT FUNCTIONAL GROUP ISOMERISM

Slide 26: 

Carboxylic Acids GENERAL FORMULA EXAMPLES HCOOH methanoic acid CH3COOH ethanoic acid CH3CH2COOH propanoic acid Illustrate the structures of these examples – show & name the corresponding aldehyde isomer. Acidic reaction CH3COOH + H2O  CH3COO- + H3O+

FORMATION OF ESTERS : 

FORMATION OF ESTERS GENERALLY: ACID + ALCOHOL ESTER + WATER catalysed by H+ ions normally from conc. H2SO4 O O R C + H O R/ R C + H2O OH O R/ O O H C + CH3OH H C + H2O OH O CH3 methanoic methanol methyl methanoate CH3CH2OH + CH3CH2COOH CH3CH2COOCH2CH3 + H2O ethanol propanoic ethyl propanoate

NAMING OF ESTERS : 

NAMING OF ESTERS GENERALLY: ACID + ALCOHOL ESTER + WATER ESTER NAME: ALCOHOLYL ACIDANOATE CH3CH2OH + CH3CH2COOH CH3CH2COOCH2CH3 +H2O ethanol propanoic ETHyl PROPanoate methanoic methanol METHyl METHanoate

HYDROLYSIS OF ESTERS : 

HYDROLYSIS OF ESTERS Hydrolysis can take place in either acid or alkaline solution Hot alkaline solution is usually preferred Ester is hydrolysed to alcohol and sodium salt of acid. Generally RCOOR’ + NaOH ROO-Na+ + R’OH EXAMPLES CH3COOCH2CH3 + NaOH CH3COO-Na+ + CH3CH2OH ethyl ethanoate sodium ethanoate ethanol CH3CH2COOCH3 + NaOH CH3CH2COO-Na+ + CH3OH methyl propanoate sodium propanoate methanol Addition of dil.H2SO4 or dil. HCl to sodium salt regenerates the carboxylic acid.

USES OF ESTERS : 

USES OF ESTERS esters have characteristic sweet smells and are used as food flavourings. they are also widely used as solvents and as plasticisers

NATURALLY OCCURING ESTERS : 

NATURALLY OCCURING ESTERS Occur as fats and oils, known as triglycerides Triesters of long-chain carboxylic acid and propane –1,2,3-triol (glycerol). On hydrolysis using hot NaOH, 3 moles of long chain acid are produced together with 1 mole of glycerol. C17H35COOCH2 CH2OH C17H35COOCH + 3NaOH CHOH + 3C17H35COONa C17H35COOCH2 CH2OH sodium glycerol stearate Sodium stearate is used in the manufacture of soap.

AMINES : 

AMINES

AMIDES : 

AMIDES

Physical Properties : 

Physical Properties Recognize and apply to particular examples the relationship between melting points, boiling points, vapour pressure, viscosity and intermolecular forces (hydrogen bonding, Van der Waals forces including dispersion or London forces number and type of functional group, chain length, branched chains)

Addition reactions : 

Addition reactions Unsaturated compounds undergo addition reactions to form saturated compounds e.g. CH2=CH2 + Cℓ2 → CH2Cℓ-CH2Cℓ - hydrohalogentaion - addition of HX - halogenation - addition of X2 – hydration - addition of H2O – The X-atom or OH-group attaches to the more substituted C-atom.) hydrogenation - addition of H2 (During additon of HX and H2O to unsaturated hydrocarbons, the H-atom attaches to the C-atom already having the greater number of H-atoms. ·

Elimination reactions : 

Elimination reactions * Saturated compounds (haloalkanes, alcohols, alkanes) undergo elimination reactions to form unsaturated compounds e.g. CH2Cℓ-CH2Cℓ → CH2=CHCℓ + HCℓ - dehydrohalogentaion - elimination of HX from a haloalkane (alkene with the more highly substituted double bond is the major product). – dehydration - elimination of H2O from an alcohol (alkene with the more highly substituted double bond is the major product). – dehydrogenation - elimination of H2 from an alkane. - cracking of alkanes. ·

Substitution reactions : 

Substitution reactions * Reactions of HX with alcohols e.g. (CH3)3OH + HBr → (CH3)3Br + H2O Reactions where the OH of alcohols are substituted with a halogen e.g. (CH3)3Br + KOH → (CH3)3OH + KBr Two types of saturated structure can be inter-converted by substitution as shown in the above two reaction equations. * Reactions of X2 with alkanes in the presence of light (prior knowledge from Grade 11).

Ionic bonding: Li + O : 

Ionic bonding: Li + O 2Li + O [Li]2+[O]2– or 4Li + O2 2[Li]2+[ O]2–

Ionic bonding: Al + Cl : 

Ionic bonding: Al + Cl

Ionic bonding: Al + Cl : 

Ionic bonding: Al + Cl Al + 3Cl [Al]3+[Cl]3–

Covalent bonding : 

Covalent bonding Thus far we have looked at when atoms bond due to the transfer of electrons An ionic bond forms when an atom has a greater attraction for e–s than a second atom However, if two atoms have approximately the same pull on electrons, they share the electrons (forming a “covalent” bond) “Covalent bonding” and “Covalent bonding continued”.

Covalent bonding : 

Covalent bonding CCl4 - Covalent HCl - Covalent MgF2 - Ionic H2O - Covalent NH3 - Covalent NaCl - Ionic OH– - Covalent H2 - Covalent

Multiple bonds : 

Multiple bonds HCl - Covalent CO2 - Covalent Na2O - Ionic O2 - Covalent I2 - Covalent Al2O3 - Ionic NH3 - Covalent O3 - Covalent

THANK YOU : 

THANK YOU