TJC 2025 Introduction to Organic Chemistry Notes (Student)

1 Temasek Junior College Integrated Programme Year 4 Chemistry Topic 10.1: Introduction to Organic Chemistry Notes Name: Class: Date: Learning objectives At the end of this notes, you must be able to: (a) name natural gas, mainly methane, and crude oil as non-renewable sources of energy (b) describe crude oil as a mixture of hydrocarbons and its separation by fractional distillation to yield fractions which have competing uses as fuels and as a source of chemicals (c) describe biofuel (exemplified by bioethanol from sugarcane) as a renewable alternative to natural gas and crude oil (d) describe how biofuel, when compared to fossil fuels, can be more environmentally sustainable in terms of carbon dioxide emission (e) interpret, and use the nomenclature, general formulae and displayed formulae of the following classes of compounds: (i) hydrocarbons (alkanes and alkenes) (ii) halogen derivatives (halogenoalkanes) (iii) alcohols (iv) carboxylic acids and esters (f) interpret, and use the following terminology associated with organic reactions: (i) functional group (ii) addition, substitution, elimination, condensation, hydrolysis (iii) oxidation and reduction [in equations for organic redox reactions, the symbols [O] and [H] are acceptable] (g) describe constitutional (structural) isomerism Useful references: Books 1. A-level Chemistry (E. N. Ramsden) 2. A Self-Study Guide to the Principles of Organic Chemistry, Jiben Roy 3. GCE ‘O’ Level Chemistry Matters (Y.T. Tan, L. K. Chen, J. Sandler & E. Clare) Websites 1. Virtual Text of Organic Chemistry (William Reusch, Michigan State University): https://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/textindx.htm 2. Chemguide (Jim Clark): http://www.chemguide.co.uk/orgmenu.html 3. Basic IUPAC Organic Nomenclature (Ian Hunt, University of Calgary): http://www.chem.ucalgary.ca/courses/351/WebContent/orgnom/index.html

2 Topic Outline 1 Introduction 1.1 Importance of Organic Chemistry 1.2 Unique Bonding Nature of Carbon 2 Primary Sources of Organic Compounds 2.1 Crude Oil and Natural Gas 2.2 Separating Crude Oil via Fractional Distillation 2.3 Catalytic Cracking 2.4 Usage of Fossil Fuels 2.5 Biofuel as Alternative Fuels 3 Classes of Organic Compounds 3.1 Saturated and Unsaturated Compounds 3.2 Functional Groups and Homologous Series 4 Representations of Organic Compounds 5 Nomenclature (Naming) of Organic Compounds 6 Types of Organic Reactions 7 Isomerism 7.1 Constitutional Isomerism 7.1.1 Chain Isomerism 7.1.2 Positional Isomerism 7.1.3 Functional Group Isomerism

3 1 Introduction • Organic chemistry involves the study of the structures, reactions, syntheses and properties of carbon-containing compounds. • Hydrocarbons are organic compounds containing ___________________________. • Not all carbon -containing compounds, however, are classified as organic compounds; examples of such exceptions are the oxides of carbon (e.g. CO or CO2), metal carbides (e.g. TiC) and carbonates (e.g. CaCO3 or H2CO3). 1.1 Importance of Organic Chemistry • It is a field of chemistry of immense importance to our daily lives and technology. • Knowledge and application extend into domains such as the: ➢ industrial manufacture of dyes, paints, plastics, fuels, drugs and polymers ➢ understanding of organic and biological matter (e.g. carbohydrates, proteins and fats) in food ➢ development of biochemistry and molecular biology 1.2 Unique Bonding Nature of Carbon • Carbon is unique in its ability to form strong covalent bonds readily with other carbon atoms to form longer chains, rings and structures. This accounts for the presence of a vast number of organic compounds in nature. • Carbon has an electronic configuration of _______________ • With 4 valence electrons, each carbon atom is able to form 4 covalent bonds where these can be single, double or triple bonds. Possibilities in a molecule include: ➢ 4 single C–C bonds ➢ 2 single C–C bonds and 1 double C=C bond ➢ 1 single C–C bond and 1 triple C≡C bond ➢ 2 double C=C bonds

4 2 Primary Sources of Organic Compounds 2.1 Crude Oil and Natural Gas Definition of fossil fuels Fossil fuels are fuels (including crude oil and natural gas ) formed by natural resources such as buried dead organisms, due to heat and pressure acting on these organisms and anaerobic decomposition of these organisms. Seed the Future Planting roots for a sustainable tomorrow For your information: [DID YOU KNOW?] Singapore is committed to sustainable energy use with the aim of reducing our greenhouse gas emissions and adhering to our commitments under the Paris Agreement on climate change. To this end, we are constantly exploring innovative ways to reduce our carbon footprint. For instance, competition in the liberalised power generation sector has spurred power generat ion companies to switch from steam plants powered with fuel oil to more efficient Combined Cycle Gas Turbines (CCGTs) fuelled by natural gas, the cleanest fossil fuel. [DID YOU KNOW?] Liquefied Natural Gas (LNG) enhances our energy security as it allows us to source for natural gas globally. To meet Singapore’s gas demand, a two-stage Request for Proposal (RFP) was launched in June 2014 to appoint up to two new LNG importers to supply Singapore’s next tranche of LNG. The appointment of two new LNG importers and the flexibility for any gas user to source LNG from the spot market contribute to the development of more competitive and dynamic gas and electricity markets in Singapore. Fossil Fuels Crude oil Natural gas Crude oil is a liquid mixture of different hydrocarbons of different molecular weights (that is found in geologic formations beneath Earth’s surface) Natural gas is a naturally occurring hydrocarbon gas mixture, primarily consisting methane (impurities include carbon dioxide). It is typically found above the crude oil layer.

5 2.2 Separating Crude Oil via Fractional Distillation Definition of fractional distillation Fractional distillation is a separation technique that is used to sepa rate a liquid mixture comprising of components with different boiling points. Boiling points increase with increasing Mr due to the _______________________________. This leads to ______________and _____________________________________________. Thus, ___________________is needed to overcome these intermolecular forces of attraction for larger alkanes during boiling. Seed the Future Planting roots for a sustainable tomorrow For your information: [DID YOU KNOW?] In SG Green Plan 2030, under the Green Economy pillar, it was announced that Jurong Island, which is known for its refineries carrying out fractional distillation of crude oil, will become a sustainable energy and chemicals park. You can read more about this ambitious undertaking in the link here. Question: Predict whether CH4 or C8H18 would have a higher boiling point. Explain why. Answer:

6 Summary of processes in fractional distillation used to separate crude oil into the various components 1. At the bottom of the fractionating column, crude oil is heated into vapour. 2. The vapour is pumped into a fractionating column where it is cool at the top but hot at the bottom. 3. As the hot vapour rises, it cools down . The smaller hydrocarbons (i.e. the hydrocarbons with lower boiling point s) are collected at the top of the fractionating column (as gases) while the larger hydrocarbons (i.e. the hydrocarbons with higher boiling points) are collected at the bottom of the column. Figure 1: Fractionating Column for Crude Oil Separation Bigger hydrocarbon molecules with hi