Organic Chemistry - Introduction Organic chemistry is the study of carbon compounds. It’s the most versatile element on the table! Animals, plants, and other forms of life consist of organic compounds. Nucleic acids, proteins, fats, carbohydrates, enzymes, vitamins, and hormones are all organic compounds. Copyright © Houghton Mifflin Company. All rights reserved. Intro

Hydrocarbons are the most simple organic compounds. Hydrocarbons contain only carbon (C) and hydrogen. (H) Copyright © Houghton Mifflin Company. All rights reserved. Section 14.2

Alkanes are hydrocarbons that contain only single bonds. Alkanes are said to be saturated hydrocarbons The have the maximum number of hydrogen atoms possible. Alkane general formula  CnH(2n + 2) The names of alkanes all end in “-ane.” Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

A New Naming System!!! The prefix for an alkane is important. It tells us how many carbons are part of the molecule. 1 Carbon = “Meth” 6 Carbons = “Hex” 2 Carbons = “Eth” 7 Carbons = “Hept” 3 Carbons = “Prop” 8 Carbons = “Oct” 4 Carbons = “But” 9 Carbons = “Non” 5 Carbons = “Pent” 10 Carbons = “Dec” Copyright © Houghton Mifflin Company. All rights reserved.

Mnemonic for First Four Prefixes Monkeys Eat Peeled Bananas First four prefixes Meth- Eth- Prop- But-

Alkanes – What are they good for? Methane = primary component of natural gas Propane & Butane = primary component of bottled gas Gasoline = pentane to decane Kerosene = alkanes with n = 10 to 16 Alkanes with n > 16  diesel fuel, fuel oil, petroleum jelly, paraffin wax, lubricating oil, and asphalt Alkanes are found in paints, plastics, drugs, detergents, insecticides, and cosmetics. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Complete Structural Formulas Show the bonds between each of the atoms H H   H  C  H H C H CH4 , methane In methane, CH4 the four valence electrons of carbon are shared with the single electrons of four hydrogen (H) atoms. Each pair of electrons is a single bond, which can be drawn as a line. When a structure is drawn to show each bond, it is called a complete structural formula. Timberlake LecturePLUS

H H Condensed Structural Formulas H C C H CH3 CH3 H H Ethane H H H H C C C H CH3 CH2 CH3 H H H Propane The complete structural formula for ethane shows the single bonds between two carbon atoms and six H atoms. The complete structural formula of propane shows the 3-carbon chain with single bonds to the attached H atoms. To write a condensed structural formula, the H atoms are written as a group next to their respective C atoms.

Practice – Naming! A. What is the condensed formula for H H H H H C C C C H B. What is its molecular formula? C. What is its name? Copyright © Houghton Mifflin Company. All rights reserved.

Additional Notes Copyright © Houghton Mifflin Company. All rights reserved.

Isomers Molecules that have the same molecular formula but different structural formulas In the case of many alkanes there is more than one way to arrange the atoms. I know it can seem a bit overwhelming, but no worries. There is a system of naming that allows us to determine how to name all Organic Compounds. IUPAC – International Union of Pure and Applied Chemistry A standardized way to write chemical compounds. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

For example butane and 2-methylpropane. Both of these alkanes have the molecular formula of C4H10 but their structural formula and arrangement is quite different. C4H10 C4H10 Copyright © Houghton Mifflin Company. All rights reserved.

What is different and unique about this molecule? It’s called a branched Alkane! How many total carbons make it up? But it’s not simply hexane. The Carbons are not all in a straight line. This is an example of a “methyl” group. A 1 carbon “side chain” off of a 5 carbon “backbone” Copyright © Houghton Mifflin Company. All rights reserved.

Alkyl Groups Alkyl group contains one less hydrogen than the corresponding alkane. Think of it as adding a CH3 group to a carbon. In naming this group the “-ane” is dropped and “-yl” is added. For example, methane becomes methyl. Ethane becomes ethyl. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Alkyl Group These groups do not exist independently but occurs bonded to another atom or molecule. Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

An Example to Consider 2-methylpentane Start by finding the longest continuous chain of Carbon atoms. This is going to be a __________. Is there anything interesting attached? Number the carbons so that it has the lowest number possible. What is the interesting thing? And what number carbon is it on? Copyright © Houghton Mifflin Company. All rights reserved. Section 14.3

Another Example to Consider First draw and then name the following molecule: CH3CH2CH(CH2CH3)CH2CH3 3-ethylpentane What’s the longest carbon chain? What’s the interesting thing? What’s the lowest possible number it can be on? Copyright © Houghton Mifflin Company. All rights reserved.