Organic Chemistry Past Paper PDF

Organic Chemistry  COURSE CONTENTS Content. number Classes of organic compounds 1 General properties of organic compounds 2 Writing organic formula 3 alkanes 4 The alkyl group...

Organic Chemistry  COURSE CONTENTS Content. number Classes of organic compounds 1 General properties of organic compounds 2 Writing organic formula 3 alkanes 4 The alkyl group 5 IUPAC Rules for nomenclature 6 Bond formation 7 Reactions 8 Cycol alkanes 9 Alkene 10 Classes OF Dienes 11 Bond formation of alkenes 12 Preparation of alkenes 13 Reactions of alkenes 14 Alkynes 15 Nomenclature 16  Bond formation 17 Preparation 18 Reactions 19 Chemistry of the functional groups 20 Alkyl halides 21 Preparation 23 Reaction 25 Alcohols 27 Nomenclature 27 Classes 28 Preparation 28 Nucleophiles 29 Electrophiles 30 Reactions 31 Ethers preparation and reactions 32 Aldehyde and ketones 33 Nomenclature 34 Preparation 35 Reactions 36 Carboxylic acid 37 Preparation 38  Reactions 39 40 Ester 41 Nomenclature 42 Preparation 43 Reactions 44 Midterm exam 45 Amines 46 Nomenclature 47 Basicity of amines 48 Preparation 49 Reactions 50 Physical properties of organic compounds 51 Stereo chemistry 52 Aromatic hydrocarbons 53 Kekule structure of benzene 54 Nomenclature of benzene substituents 55 Poly cyclic aromatic hydrocarbons 56 Physical properties of arenes 57 Reactions of benzene Heterocyclic aromatic compounds 58 Aromaticity of benzene 59 Huckel rule 60 References:- Organic chemistry by Chang. Organic chemistry by Carey. Organic chemistry by Paula Bruice.  OrganicChemistry: Is the chemistry of the compounds that contains carbon atom. The chemistry of the hydrocarbon and their derivatives. Organic chemistry based on: 1- Carbon atom have a valency of 4 ( ability to form 4 covalent bond with other atoms). 2- Carbon atom has ability to form chains: a- straight chain b- branched chain c- cyclic chain 3- Carbon atom has ability to form multiple bonds (double and triple bond).  Derivatives of Hydrocarbons: Derivative Functional Group Alkyl Halides R─X Alcohols R─OH Ethers R─O─R` Aldehydes R ─CO ─H Ketones R ─CO ─R` Esters R ─COO ─R` Carboxylic acids R ─COOH Amines R ─NH2 Amides R ─CO ─NH2 Nitriles R ─CN  Homologous Series: 1- Is a group of organic chemical cpds usually listed in order of increasing size, that have a similar structure and hence also similar properties and whose structure differ only by the number of CH2 units in the main carbon chain. 2- Is a family of hydrocarbons with similar chemical properties who share the same general formula. General properties of organic compounds:- Mostly covalent compounds. Low boiling point. Low solubility in water and have a tendency to dissolve in organic solvent ---- like dissolves like. Hydrocarbons are generally non polar, where as organic derivatives have a varied polarity according to the functional group. Mostly inflammable and non conductors to electricity. Ability to form large molecules (polymers). Most aromatic compounds are toxic with undesirable odor.  The boiling point and solubility depend on: 1- The polarity of the functional group. 2- Ability to form the hydrogen bond. 3- Number of carbon atoms. The M.P. and B.P. depends on: 1- The molecular weight. 2- structure of the cpd. 3- intermolecular forces between the atoms. Notes: Carboxylic acids are the most polar derivatives and more polar than alcohols because the carbonyl group increase the electro negativity of the oxygen so it is more soluble. All organic cpds with less than 6 carbon atoms are soluble water. Hydrocarbons with less than 5 carbons atoms are gases. The most polar organic cpds will have the highest B.P. and highest tendency to dissolve in water Alcohols are more polar than Amine, because the oxygen is more electronegative than nitrogen.  Tertiary Amines cannot form hydrogen bond, because the nitrogen bonded with 3R groups. (have low boiling point and solubility than 2° and 1° amines). Hydrocarbons are non-polar, because they are contains only C and H. Ethers have lowest polarity among the derivatives, because the H-bond is absent and the O atom in the middle. Aldehydes are more polar than ketones, because the aldehydes have acidic H.  General formula: describes the kind of atoms in a molecules and exact number of atoms. Structural formula: it states exactly how the atoms are bonded and also describe the kind and number of atoms. Functional group: is an atom or group of atoms that is responsible for the chemical and physical behavior of the molecules.  Writing the organic formula: 1- Empirical formula: the simplest ratio. C6H12O6 divided over the lower number CH2O. 2- Molecular formula: CH3CH2CH3 3- Condensed formula: CH3CH2CH2CH2CH2CH2CH3 CH3(CH2)5CH3 4- Line dot formula:  Isomerism: Isomerism in organic chemistry is a phenomenon shown by two or more organic compounds having the same molecular formula but different properties due to difference in arrangement of atoms along the carbon skeleton (structural isomerism) or in space (Stereo isomerism). 1-Structural isomerism Chain Isomerism It occurs when carbon atoms are linked to the main chain in different ways. 1-Structural isomerism Position Isomerism It occurs when functional groups are attached on different positions on a carbon chain.  1-Structural isomerism Functional Isomerism compounds are different due to different arrangements of atoms leading to different functional groups. As functional groups are usually the reactive centre of a molecule this leads to entirely different properties. 2- Stereoisomerism.: the differ in the arrangement of atoms in the spaces. a) Optical isomerism: Are mirror images for each other. b) Geometrical isomerism.: Differ in the free rotation around double bond. Define: 1- Melting point. 2- Boiling point. 3- Solubility. 4- Polarity. 5- Density. 6- Covalent bond. 7- Hydrogen bond. 8- Hydrocarbon. 9- Saturated cpd. 10- Unsaturated cpd. ^_^  Alkanes: Is hydrocarbon molecules that contain only single bond (functional group). Is saturated hydrocarbon because they contain the maximum number of hydrogen atoms that can bond with number of the carbon atoms present. General formula: CnH2n+2 n= 1,2,3,…… Structural formula: R─R` or R─H Functional group: Single bond Examples of Alkanes: Name Molecular formula No. of C atoms Methane CH4 1 Ethane CH3CH3 2 Propane CH3CH2CH3 3 Butane CH3CH2CH2CH3 4 Pentane CH3(CH2)3CH3 5 Hexane CH3(CH2)4CH3 6 Heptane CH3(CH2)5CH3 7 Octane CH3(CH2)6CH3 8 Nonane CH3(CH2)7CH3 9 Decane CH3(CH2)8CH3 10  The alkyl groups: Name Formula General formula: Methyl CH3─ CnH2n+1 Ethyl CH3CH2─ Structural formula: n- Propyl CH3CH2CH2─ R-1 n- Butyl CH3CH2CH2CH2─ Iso- Butyl CH(CH3)2CH2─ Sec. Butyl CH3CH2CHCH3 t- Butyl C(CH3)3─ Neo- Pentyl C(CH3)3CH2─  Nomenclature of alkanes: 1- IUPAC Name 2- Common Name A) IUPAC: International Union of Pure and Applied Chemistry 1- Select the longest continuous chain: 2- Identify the various branches groups attached to this continuous chain: 3- More than one alkyl branch or the same kind present, we use prefix such as (di, tri, and tetra…..etc.) with the name of alkyl group. 4- When there are two or more different alkyl groups, the name of the groups are listed alphabetically.  Common name: In the common names we have the prefixes n, iso, α, β, δ, and γ. n ≡ Straight Chain. iso ≡ alkyl group that has a single one carbon branch on the next two last carbon of a chain and has the point of attachment at opposite end of the chain.  Examples of names of alkanes: Structure IUPAC name Common name CH3CH2CH3 Propane n- propane CH3CH2CH2CH3 Butane n- butane CH3CH(CH3)CH3 2- methyl iso- butane propane C(CH3)4 2,2- di methyl Neo- pentane propane CH3(CH2)4CH3 hexane n- hexane CH3CH(CH3)CH2CH2 2- methyl iso- hexane CH3 pentane CH3CH(CH3)CH2CH2 1- chloro-3- iso- Pentyl Cl methyl butane chloride.  Preparation of alkanes: 1-Reduction OF alkyl halides: Hydrolysis of Grignard reagent. RX + Mg → RMgX(Grignard reagent) →+H2O→ RH(alkane) CH3CH2CHBr CH3 + Mg Dry ether CH3CH2CHMgBrCH3 CH3CH2CHMgBrCH3+ H2O → CH3CH2CH2CH3  Preparation of alkanes: 2- Coupling of alkyl halides with organometallic compounds:  Reactions of Alkanes: 1-Halogenation ( substitution)  Reactions of Alkanes: 2-Cracking (Pyrolysis)reaction of alkanes:  Reactions of Alkanes: 3- Combustion ( addition of oxygen ) CnH2n+2 + O2 → CO2 + H2O + ΔH (Kg/mol) CH4 + O2 → CO2 + H2O + ΔH ( -890.4Kg/mol) 2C2H6 + 7O2 → 4CO2 + 6H2O + ΔH(-3119 Kg/mol  Alkenes: Alkenes also called olefins contain at least one carbon- carbon double bond. General formula: CnH2n where n= 2, 3, 4, 5,……. The simplest alkenes is ethylene (Ethene) C2H4 Structural formula: RC=CR` Functional group: double bond  Nomenclature of alkenes IUPAC names: 1- Select the longest continuous chain containing the functional group (in this case, the carbon-carbon double bond) is numbered in a direction that gives the functional group suffix (carbon atom of functional group) the lowest possible number. 2- the name of the substituent is cited before the name of the longest continuous chain containing functional group, together with a number to designate the carbon to which the substituent is attached. 3- If a chain has more than one substituent, the substituent are cited in alphabetical order, using the same rules for alphabetizing that you learned in alkanes. 4- In cyclic alkenes, the double bond is between carbons 1 and 2. Common names:  Dienes Compounds: Hydrocarbons that contains two double bonds is called alkadiene. Classes of Dienes compounds: The relationship between the double bonds is described as: (1) Isolated (2) Conjugated (3) Accumulated Isolated Dienes: The two double bonds are separated from each other by one or more sp3- hybridization carbon atoms.  Conjugated Dienes: The two double bonds are connected to each other by a single bond. Accumulated Dienes: One carbon atoms is common to two carbon-carbon double bonds.  Preparation of alkenes: 1- Dehydrohalogenation of alkylhalides: CH3CH2X + KOH → CH2= CH2 + KX + H2O Ease 3⁰ > 2⁰ > 1⁰ CH3CH2CH2Cl + KOH alcohol → CH3CH=CH2 + KCl + H2O  Preparation of alkenes: 1- Dehydrohalogenation of alkylhalides:  Preparation of alkenes: 2- Reduction of alkynes: RC≡CR + H2 (lindlar catalyst) → RC=CR (cis) RC≡CR + H2 (Na or Li/ NH3) → RC=CR (trans)  Reactions of alkenes: Alkenes are classified as unsaturated hydrocarbons with double carbon- carbon bonds that enable them to add hydrogen atoms. Unsaturated hydrocarbons commonly undergo addition reaction.  Reactions of alkenes: 1-Addition of halogen halides ( halogen acids) {Markovnikov addition}: 2- Addition of sulphuric acid:  Reactions of alkenes: 3- Addition of water ( Hydration): 4- Hydroxylation:  Reactions of alkenes: 5- Hydroboration- oxidation: Borane is commercially available in ether and tetrahydrofuran (THF) 2BH3→B2H6  Alkynes: Hydrocarbons contain at least one carbon-carbon triple bond. General formula: CnH2n-2 where n= 2, 3, 4, 5,……. The simplest alkynes is ethyne C2H2 Structural formula: RC≡CR` Functional group: triple bond  Nomenclature of alkynes: a) IUPAC names: 1- Select the longest continuous chain containing the functional group (in this case, the carbon-carbon triple bond) is numbered in a direction that gives the functional group suffix (carbon atom of functional group) the lowest possible number. 2- the name of the substituent is cited before the name of the longest continuous chain containing functional group, together with a number to designate the carbon to which the substituent is attached. 3- If a chain has more than one substituent, the substituent are cited in alphabetical order, using the same rules for alphabetizing that you learned in alkanes and alkenes. 4- In cyclic alkynes, the triple bond is between carbons 1 and 2.  Preparation of alkynes: 1-Dehydrohalogenation of alkyl dihalides: (gem-dihalide) geminal dihalide (both halogens on the same carbon) or (a vic- dihalide) a vicinal dihalide (halogens on adjacent carbons)  Preparation of alkynes: 1-Dehydrohalogenation of alkyl dihalides:  Preparation of alkynes: 2-Reduction of metal acetylides with primary alkyl halides:  Preparation of alkynes: 2-Reduction of metal acetylides with primary alkyl halides:  Reactions of alkynes: 1-Addition of hydrogen : C2H2 + H2 → C2H4 + H2 → C2H6  Reactions of alkynes: 2-Addition of halogen and hydrogen halides :  Reactions of alkynes: 3-Hydration (Tautomerism):  Reactions of alkynes: 3-Hydration (Tautomerism): Write the IUPAC names of the following cpds: