NJC Organic Chem 2023 Book 1 Student Version

National Junior College SH1 H2 Chemistry 2023 H2 Chemistry Organic Booklet 1 Contents 0 Learning Outcomes for Organic Chemistry 1 Introduction to Organic Chemistry 2 Isomerism 3 Alkanes 4 Alkenes 5 Arenes References 1. Chemistry for Advanced Level by P. Cann & P. Hughes, published by John Murray 2. A-Level Chemistry (4th Edition) by E. N. Ramsden, published by Nelson Thornes 3. Understanding Chemistry for Advanced Level (3rd Edition), by T. Lister & J. Renshaw, published by Nelson Thornes 4. Chemistry in Context (5th Edition) by Hill & Holman, published by Nelson Thornes 5. Chemistry in Context Laboratory Manual and Study Guide (5th Edition) by Hill & Holman, published by Nelson Thornes 6. ILPAC Advanced Practical Chemistry (2nd edition) by A. Lainchbury, J. Stephens, A. Thompson, published by John Murray 7. A2 Chemistry, 2nd edition, Geroge Facer 8. Longman A-level course in Chemistry, 7th edition, JGR Briggs 9. Organic Chemistry, 5th edition, John McMurry Copyright © 2023 National Junior College All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording or any other information storage and retrieval system, without prior permission in writing from the copyright owner.

National Junior College SH1 H2 Chemistry 2023 Organic Chemistry Preamble

National Junior College SH1 H2 Chemistry 2023

National Junior College SH1 H2 Chemistry 2023

National Junior College SH1 H2 Chemistry 2023

National Junior College SH1 H2 Chemistry 2023

National Junior College SH1 H2 Chemistry 1 1 INTRODUCTION TO ORGANIC CHEMISTRY 1.1 THE ORIGINS OF ORGANIC CHEMISTRY The modern definition of organic chemistry is the study of compounds that contain carbon. Originally, the science of organic chemistry was the study of compounds extracted from living organisms and their natural products. In 1807, Jon Jacob Berzelius classified chemical compounds into two main groups: those with origin from living or once- living matter, which he termed organic and those that originated from “mineral” or non-living matter, which he termed inorganic. Berzelius, similar to most chemists of that era, believed that organic compounds could only come from living organisms mediated by some vital force, known as Vitalism.] In 1828, Frederich Wöhler, ironically a student of Berzelius, discovered that the org anic compound, urea, could be made by heating ammonium cyanate, an inorganic salt. This demonstrated for the very first time that an organic compound can be synthesised from an inorganic source, which led eventually to the rejection of Vitalism as a scientific theory. C N-O H2N C O NH2NH4+ heat ammonium cynate urea Wöhler’s observation also marked the discovery of isomerism – the phenomenon of two or more different chemical structures based on the same chemical formula. Today, chemistry is unified and the same principle s that explain inorganic compounds explain the organic ones as well. The only distinguishing characteristic of organic compounds is that all contain the element carbon. Organic chemistry is the chemistry of carbon and its compounds, which are central to life. Carbon is present in all large and complex molecules in all living species. The diversity of life is a manifestation of the diversity of carbon chemistry. The ability of carbon to form a virtually unlimited range of compounds has led to an almost unlimited range of living organisms constructed out of molecules containing carbon. More than 10 million compounds we encounter in our daily lives are organic compounds. They are found in fuels, plastics, synthetics and natural fibers such as polyester, dyes, cottons, drugs, pesticides, preservatives, flavorings, etc. Paracetamol (Panadol) Dichlorodiphenyltrichloroethane (DDT) (Insecticide) Frederich Wöhler Jon Jacob Berzelius

National Junior College SH1 H2 Chemistry 2 1.2 REASONS FOR THE VAST VARIETY OF ORGANIC COMPOUNDS Carbon has 3 important properties that enable it to form many stable compounds. (i) Ability of carbon to form strong C−C bonds Bond Bond energy / kJ mol‒1 C–C 350 C–O 360 C–Cl 340 C–H 410 The C–C bond is strong and its strength is comparable to that of the C–O and C–Cl bonds. This ability of carbon to form strong bonds with itself leads to the formation of chains and rings of different lengths / sizes. (ii) Ability of carbon to form multiple bonds A carbon atom has 4 valence electrons, hence can form covalent bonds with as many as 4 other atoms. This gives rise to branching into side chain of other carbon atoms Carbon can also undergo different types of hybridisation (sp, sp2 and sp3) resulting in the formation of single, double and triple bonds between carbon atoms and between carbon and other atoms, leading to a greater variety of stable compounds of different structure/shapes. (iii) Kinetic stability of carbon compounds under normal conditions Methane and most other carbon -containing compounds are thermodynamically less stable than their combustion products. However, they are kinetically stable as they react only very slowly, if at all, with oxygen under normal conditions. This is mainly due to: ● strong C−C and C−H bonds. This breaking of C –C requires relatively large energy of activation. ● inability of C to expand its octet.

National Junior College SH1 H2 Chemistry 3 1.3 INTRODUCTION TO ORGANIC COMPOUNDS Success Criteria: • I can classify organic compounds into aliphatic, aromatic, acyclic and cyclic compounds. • I can explain and recognise what saturated and unsaturated organic compounds are. 1.3.1 Classifications of Organic Compounds Saturated and unsaturated organic compounds An organic compound which contains only single bonds (C –C and C –H bonds in hydrocarbons) is said to be saturated. C CH H H H H H An organic compound which contains 1 or more double / triple bonds (C=C, C=O and C≡N bonds) is said to be unsaturated. C CH H H H

National Junior College SH1 H2 Chemistry 4 1.3.2 Structural Formulae of Organic Compounds Success Criteria: • I can interpret and draw different types of structural formulae (eg condensed, displayed, skeletal and stereochemical). Lactic acid has a molecular formula of C 3H6O3 and an empirical formula of CH2O. A molecular formula does not show how the various atoms in the organic compound are actually connected to one another. Hence, structural formulae are used to represent organic compounds. Below are the different structural formulae of lactic acid, CH3CH(OH)CO2H. Type of Structural Formulae Representation Characteristics Condensed CH3CH(OH)CO2H ● shows the order of arrangement of atoms ● bonds are not displayed Displayed / Full structural ● shows all atoms and bonds in the molecule Skeletal ● Carbon atoms in a straight chain are drawn in a zigzag manner ● each end of a line represents a carbon if other symbol of an atom is not written ● C–H bonds at each C are not shown. ● each C forms 4 bonds. Any “missing” bond not drawn out in a skeletal structure would be a C–H bond. Stereochemical (for optical isomers where a C has four different groups attached) CH3 H CO2H OH or ● shows 3-D spatial arrangement of bonds, atoms and / or groups of atoms in a molecule ● a dashed li