Organic Chemistry

18.1 - Fuels and Crude oils Main Sources of electricity, also known as hydrocarbons. Formed by decomposition of plants and animals that lived millions of years ago. Hence it is finite resource 18.2 - Separation of crude oil 18.3 - Competing Uses of Different crude oil fractions

18.3.1 - Are biofuels more environmentally sustainable 19.1 - Hydrocarbon Definition: An organic compound which contain ONLY carbon and hydrogen Carbon has 4 valence electrons and can bond with many other elements. Hence it can form many types of compounds. For example:

19.1.1 - Homologous Series Definition: A family of organic compounds with the same general formula and similar chemical properties due to the presence of same functional group Properties: 1. Same general formula, 2. Mr differs by 14 from one member to another due to an extra CH 2 present Increase in carbon atoms = 3. mp and bp ↑ 4. Viscosity ↑ 5. Density ↑ 6. Solubility ↓ 7. Similar chemical properties due to the presence of same functional group 19.1.2 - Naming of organic compounds Number of carbon atoms Prefix 1 meth- 2 eth- 3 prop- 4 but- 5 pent- 6 hex- 7 hept- 8 oct- 9 non- 10 dec- Type of compound Suffix Alkane -ane Alkene -ene Alkyne -yne Alcohol -ol Carboxylic acid -oic acid

19.1.3 - Substituent group Definition: An atom or group of atoms that replaces a hydrogen atom on the main carbon chain. Substituent Formula Prefix used in naming Fluorine –F fluoro- Chlorine –Cl chloro- Bromine –Br bromo- Iodine –I iodo- Methyl –CH ₃ methyl- Ethyl –C ₂ H ₅ ethyl- 19.1.4- Alkyl groups Definition: Formed when you remove one hydrogen atom from an alkane. Alkane Alkyl group Formula Methane Methyl –CH ₃ Ethane Ethyl –C ₂ H ₅ Propane Propyl –C ₃ H ₇ Butane Butyl –C ₄ H ₉ Pentane Pentyl –C ₅ H ₁₁ Hexane Hexyl –C ₆ H ₁₃ 19.1.5 - Same substituent group appears more than once Number of same substituents Prefix 2 di- 3 tri- 4 tetra- 5 penta-

19.2 - Alkanes Definition: Saturated hydrocarbons containing only single covalent bonds between carbon atoms. ( Therefore contain maximum possible number of hydrogen atoms per carbon) General formula: C n H 2n+2 End with -ane 19.2.1 - Physical properties 1. Low mp, bp as they have simple molecular structure, so the weak intermolecular forces of attraction between the molecules need only a small amount of energy to overcome 2. As number of carbon atoms increase, mp bp,density increase, ( Molecular size increase) 3. More viscous ( Molecular size increase) 4. As number