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Organic Chemistry UNIT 1 CONTENTS At this moment, you are walking, CHAPTER 1 sitting, or standing in an “organic” Classifying Organic Compounds body. Your skin, hair, muscles, heart, CHAPTER 2 and lungs are all made from organic Reactions of Organic Compounds compounds. In fact, the only parts of your body that are not mostly organic UNIT 1 ISSUE are your teeth and bones! When you Current Issues Related to study organic chemistry, you are Organic Chemistry studying the substances that make up your body and much of the world UNIT 1 OVERALL EXPECTATIONS around you. Medicines, clothing, carpets, curtains, and wood and How do the structures of various organic compounds plastic furniture are all manufactured differ? What chemical from organic chemicals. If you look reactions are typical of these out a window, the grass, trees, squir- compounds? rels, and insects you may see are also How can you name different composed of organic compounds. organic compounds and Are you having a sandwich for represent their structures? lunch? Bread, butter, meat, and lettuce What do you need to know in are made from organic compounds. order to predict the products Will you have dessert? Sugar, flour, of organic reactions? vanilla, and chocolate are also organic. How do organic compounds What about a drink? Milk and juice affect your life? How do they are solutions of water in which affect the environment? organic compounds are dissolved. In this unit, you will study a variety of organic compounds. You Unit Issue Prep will learn how to name them and how Before beginning Unit 1, read to draw their structures. You will also pages 110 to 111 to find out about learn how these compounds react, and the unit issue. In the unit issue, you you will use your knowledge to pre- will analyze an issue that involves dict the products of organic reactions. chemistry and society. You can start planning your research as you In addition, you will discover the go through this unit. Which topics amazing variety of organic compounds interest you the most? How does in your body and in your life. society influence developments in science and technology? 2 Classifying Organic Compounds Chapter Preview As you wander through the supermarket, some advertising claims catch your eye. “Certified organic” and “all natural” are stamped on the labels 1.1 Bonding and the Shape of some foods. Other labels claim that the foods are “chemical free.” As a of Organic Molecules chemistry student, you are aware that these labels may be misleading. Are 1.2 Hydrocarbons all “chemicals” harmful in food, as some of the current advertising suggests? 1.3 Single-Bonded Many terms are used inaccurately in everyday life. The word “natural” Functional Groups is often used in a manner suggesting that all natural compounds are safe 1.4 Functional Groups and healthy. Similarly, the word “chemical” is commonly used to refer to With the CϭO bond artificial compounds only. The food industry uses “organic” to indicate foods that have been grown without the use of pesticides, herbicides, fertilizers, hormones, and other synthetic chemicals. The original meaning of the word “organic” refers to anything that is or has been alive. In this sense, all vegetables are organic, no matter how they are grown. Organic chemistry is the study of compounds that are based on carbon. Natural gas, rubbing alcohol, aspirin, and the compounds that give fragrance to a rose, are all organic compounds. In this chapter, you will learn how to identify and name molecules from the basic families of Prerequisite organic compounds. You will be introduced to the shape, structure, and Concepts and Skills properties of different types of organic compounds. Before you begin this chapter, review the following concepts What is the word “organic” intended to mean here? and skills: How is this meaning different from the scientific I drawing Lewis structures meaning of the word? (Concepts and Skills Review) I writing molecular formulas and expanded molecular formulas (Concepts and Skills Review) I drawing complete, con- densed, and line structural diagrams (Concepts and Skills Review) I identifying structural isomers (Concepts and Skills Review) 4 MHR • Unit 1 Organic Chemistry Bonding and the Shape of Organic Molecules 1.1 Early scientists defined organic compounds as compounds that originate Section Preview/ from living things. In 1828, however, the German chemist Friedrich Wohler Specific Expectations (1800–1882) made an organic compound called urea, CO(NH2)2, out of an In this section, you will inorganic compound called ammonium cyanate, NH4CN. Urea is found in I discuss the use of the the urine of mammals. This was the first time in history that a compound terms organic, natural, and normally made only by living things was made from a non-living sub- chemical in advertising stance. Since Wohler had discovered that organic compounds can be made I demonstrate an under- without the involvement of a life process, a new definition was required. standing of the three types Organic compounds are now defined as compounds that are based on of carbon-carbon bonding carbon. They usually contain carbon-carbon and carbon-hydrogen bonds. and the shape of a molecule around each type of bond The Carbon Atom I communicate your under- standing of the following There are several million organic compounds, but only about a quarter terms: organic chemistry, of a million inorganic compounds (compounds that are not based on organic compounds, carbon). Why are there so many organic compounds? The answer lies in tetrahedral, trigonal the bonding properties of carbon. planar, linear, bent, As shown in Figure 1.1, each carbon atom usually forms a total of electronegativity, bond four covalent bonds. Thus, a carbon atom can connect to as many as four dipole, polar, molecular polarity other atoms. Carbon can bond to many other types of atoms, including hydrogen, oxygen, and nitrogen. H ••• Web LINK • • • • • + → • • C 4H H C H • • • www.mcgrawhill.ca/links/ H chemistry12 In the chapter opener, you Figure 1.1 This Lewis structure shows methane, the simplest organic compound. The considered how the terms carbon atom has four valence electrons, and it obtains four more electrons by forming four “natural” and “chemical” are covalent bonds with the four hydrogen atoms. used inaccurately. A natural substance is a substance that In addition, carbon atoms can form strong single, double, or triple bonds occurs in nature and is not with other carbon atoms. In a single carbon-carbon bond, one pair of artificial. A chemical is any electrons is shared between two carbon atoms. In a double bond, two substance that has been made pairs of electrons are shared between two atoms. In a triple bond, three using chemical processes in pairs of electrons are shared between two atoms. a laboratory. A chemical can also be defined as any sub- Molecules that contain only single carbon-carbon bonds are saturated. stance that is composed of In other words, all carbon atoms are bonded to the maximum number of atoms. This definition covers other atoms: four. No more bonding can occur. Molecules that contain most things on Earth. Go to the double or triple carbon-carbon bonds are unsaturated. The carbon atoms web site above, and click on on either side of the double or triple bond are bonded to less than four Web Links to find out where atoms each. There is potential for more atoms to bond to each of these to go next. Look up some carbon atoms. natural poisons, pesticides, Carbon’s unique bonding properties allow the formation of a and antibiotics that are produced by animals, plants, variety of structures, including chains and rings of many shapes and and bacteria. Then look up sizes. Figure 1.2 on the next page illustrates some of the many shapes some beneficial chemicals that can be formed from a backbone of carbon atoms. This figure includes that have been synthesized examples of three types of structural diagrams that are used to depict by humans. Make a poster to organic molecules. (The Concepts and Skills Review contains a further illustrate your findings. review of these types of structural diagrams.) Chapter 1 Classifying Organic Compounds • MHR 5 CHEM A H B C FACT H C H A few carbon compounds are considered to be inorganic. H CH These include carbon dioxide, C C CH3 C CH CO2, and and carbon com- pounds containing complex C C HHC negative ions (for example, CO 2−, HCO −, and OCN−). 3 3 H C H H Figure 1.2 (A) This complete structural diagram shows all the bonds in the molecule. (B) This condensed structural diagram shows only carbon-carbon bonds. (C) This line structural diagram uses lines to depict carbon-carbon bonds. Carbon compounds in which carbon forms only single bonds have a different shape than compounds in which carbon forms double or triple bonds. In the following ExpressLab, you will see how each type of bond affects the shape of a molecule. ExpressLab Molecular Shapes The type of bonding affects the shape and 4. Examine the shape of the molecule around movement of a molecule. In this ExpressLab, each carbon atom. Draw diagrams to show your you will build several molecules to examine the observations. shape and character of their bonds. Analysis Procedure 1. Which bond or bonds allow rotation to occur? 1. Build a model for each of the following com- Which bond or bonds are fixed in space? pounds. Use a molecular model kit or a chemical 2. (a) Describe the shape of the molecule around a modelling computer program. carbon atom with only single bonds. CH3 CH2 CH2 CH3 H2C CH CH2 CH3 (b) Describe the shape of the molecule around a carbon atom with one double bond and two butane 1–butene single bonds.