FOS 127 Foundation Organic and Analytic Chemistry PDF

FOS 127 FOUNDATION ORGANIC AND ANALYTIC CHEMISTRY  WHAT TO BE COVERED (WEEK 1) INTRODUCTION TO ORGANIC CHEMISTRY DEFINITIONS AND CONCEPTUALIZATION OF KEY CONCEPTS SUB TOPICS  Classification and application of organic compounds  Functional groups and the naming of orga...

FOS 127 FOUNDATION ORGANIC AND ANALYTIC CHEMISTRY  WHAT TO BE COVERED (WEEK 1) INTRODUCTION TO ORGANIC CHEMISTRY DEFINITIONS AND CONCEPTUALIZATION OF KEY CONCEPTS SUB TOPICS  Classification and application of organic compounds  Functional groups and the naming of organic compounds  Types of organic reactions  Hybridization of the carbon atom and shapes of organic molecules  DEFINITION OF ORGANIC CHEMISTRY AND AN ORGANIC MOLECULE  Organic chemistry is a sub discipline involving the study of the nomenclature, structure, properties and reactions of organic molecules and materials  An organic compound is any class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of elements like hydrogen, oxygen or nitrogen. Organic compounds contain carbon-carbon or carbon-hydrogen bonds.  However there are some molecules that have carbon-carbon or carbon- hydrogen bonds and are not classified as organic compounds e.g. carbonate salts, cyanide salts, and carbon dioxide.  CLASSIFICATION OF ORGANIC COMPOUNDS 1. Based on Carbon Skeleton: a. Aliphatic Compounds: These compounds have straight-chain, branched-chain, Examples include alkanes, alkenes, alkynes, and their derivatives.  Saturated Aliphatic Compounds: Contain only single bonds (e.g., alkanes).  Unsaturated Aliphatic Compounds: Contain double or triple bonds (e.g., alkenes, alkynes). b. Alicyclic Compounds: These compounds have carbon atoms arranged in a ring or cyclic structure (e.g., cycloalkanes). c. Aromatic Compounds: These compounds contain a ring with alternating single and double bonds. Benzene and its derivatives are common aromatic compounds.  2. Based on Functional Groups:  Hydrocarbons: Compounds containing only carbon and hydrogen. Examples include alkanes, alkenes, alkynes, and aromatic hydrocarbons.  Alcohols: Compounds containing the hydroxyl (-OH) functional group.  Aldehydes: Compounds with a carbonyl group (C=O) at the end of a carbon chain.  Ketones: Compounds with a carbonyl group (C=O) within the carbon chain.  Carboxylic Acids: Compounds with a carboxyl group (-COOH).  Esters: Compounds derived from the reaction between carboxylic acids and alcohols. Cont.'s  Amines: Compounds containing the amino group (-NH2) or its derivatives.  Ethers: Compounds with an oxygen atom linking two carbon atoms.  Halogenated Compounds: Compounds containing halogen atoms (fluorine, chlorine, bromine, iodine).  Amides: Compounds derived from the reaction between carboxylic acids and amines. APPLICATIONS OF ORGANIC COMPOUNDS  Are used in the production of medicine, soaps, shampoos, powders, and perfumes.  Various fuels like natural gas, petroleum are also organic compounds.  The fabrics that we use to make various dresses are also made from organic compounds  FUNCTIONAL GROUPS  A functional group is a collection of atoms within molecules which bind together to react in predictable ways.  Examples of functional groups include the group hydroxyl, carboxyl, aldehyde, ketone, amine, and ether.  Each of the functional groups has a different structure and is entirely responsible for the chemical characteristics of each of the classes of organic molecules  Note that there is one class of organic molecules that do not have a functional group i.e. alkanes and for alkenes the double bond acts as the functional group Name of family General formula functional group Suffi x Alkane RH None -ane Alkene R2C=CR2 -ene Alkyne RC≡CR –C≡C– -yne Alcohol ROH –OH -ol Thiol RSH –SH -thiol Ether ROR –O– Ether Aldehyde -al Ketone -one Carboxylic acid -oicacid  NOMENCLATURE OF ORGANIC COMPOUNDS  The IUPAC rules are followed during nomenclature. In general the base part of the name reflects the number of carbon atoms in the parent chain.  The suffix of the name reflects the functional group present on the parent chain.  Other groups which are attached to the parent chain are called substituents  NOMENCLATURE continued  When naming the branching is considered and the carbon atom with the functional group  In case of a cyclic hydrocarbon, the prefix cyclo- appears directly in front of the base name e.g. cyclo- hexane STEPS FOR NAMING ORGANIC CPDS 1. Identify the Parent Chain:  Determine the longest continuous carbon chain (main chain) in the molecule. This chain represents the backbone of the organic compound and is usually named based on the number of carbon atoms it contains (meth-, eth-, prop-, but-, pent-, etc.). 2. Numbering the Parent Chain:  Number the carbon atoms in the main chain sequentially, starting from the end nearest to a substituent (functional group or side chain). The goal is to assign the lowest possible numbers to the substituents. CONT’D 3. Naming Substituents:  Identify and name any substituent groups attached to the main chain. Common substituents include alkyl groups (methyl-, ethyl-, propyl-, etc.) and functional groups (e.g., hydroxyl group, -OH; carbonyl group, -C=O).  Use prefixes like di-, tri-, tetra-, etc., to indicate multiple substituents of the same kind. 4. Assigning Locants:  Use numbers to indicate the positions of substituents on the main chain. Assign the lowest possible numbers to the substituents, considering alphabetical order when multiple substituents are present. CONT’D 5. Naming Functional Groups:  If the molecule contains a functional group, identify and name it according to priority rules. The highest priority functional group determines the suffix of the compound's name.  For example, alcohols have the suffix "-ol," ketones have the suffix "- one," carboxylic acids have the suffix "-oic acid," etc. 6. Putting It All Together:  Combine the names of the parent chain, substituents, and functional groups to form the systematic name of the compound.  Use hyphens to separate different parts of the name and commas to separate numbers from names.  TYPES OF ORGANIC REACTIONS  An addition reaction is an organic reaction in which two (or more) molecules combine to give a single product with no other products  A substitution reaction is a reaction that involves replacing an atom or group of atoms by another  An elimination reaction is a reaction in which a small molecule (such as H2O or HCl) is removed from an organic molecule TYPES continued  A hydrolysis reaction is a reaction in which a compound is broken down by water (it can also refer to the breakdown of a substance by dilute acids or alkali)  A condensation reaction is a reaction in which two organic molecules join together and in the process eliminate small molecules (such as H2O or HCl  HYBRIDIZATION OF CARBON ATOMS  Hybridization is the idea that atomic orbitals fuse to form newly hybridized orbitals, which in turn, influences molecular geometry and bonding properties.  Types of hybridization 1. sp Hybridization- when it is bound to two other atoms with the help of two double bonds or one single and one triple bond 2. sp2 Hybridization-when bonding takes place between 1 s- orbital with two p orbitals. 3. sp3 Hybridization-When the carbon atom is bonded to four other atoms the hybridization is said to be sp3 type SHAPES OF ORGANIC MOLECULES  Shapes of simple organic molecule depends upon its hybridization state.  Like carbon shows sp3 hybridization in methane hence the shape is tetrahedral while in case ethene it shows sp2 hybridization hence the shape is trigonal planar.  Alkyne molecule shows sp hybridization hence shape is linear. sp Hybridization  Geometry: Linear  Bond Angle: 180°  Example: Ethyne (C₂H₂)  Description: In sp hybridization, one s orbital mixes with one p orbital to form two sp hybrid orbitals, which are oriented 180° apart, resulting in a linear geometry. The remaining two unhybridized p orbitals form π bonds, creating a triple bond in molecules like ethyne. sp² Hybridization  Geometry: Trigonal Planar  Bond Angle: Approximately 120°  Example: Ethene (C₂H₄)  Description: In sp² hybridization, one s orbital mixes with two p orbitals to form three sp² hybrid orbitals, lying in the same plane at 120° angles to each other. The unhybridized p orbital forms a π bond above and below this plane, giving the molecule a trigonal planar shape. sp³ Hybridization  Geometry: Tetrahedral  Bond Angle: Approximately 109.5°  Example: Methane (CH₄)  Description: In sp³ hybridization, one s orbital mixes with three p orbitals to form four equivalent sp³ hybrid orbitals. These orbitals are oriented toward the corners of a tetrahedron, leading to a tetrahedral shape.