How to Use This Presentation • To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” • To advance through the presentation, click the right-arrow key or the space bar. • From the resources slide, click on any resource to see a presentation for that resource. • From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. • You may exit the slide show at any time by pressing the Esc key. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Resources Chapter Presentation Bellringer Transparencies Sample Problems Visual Concepts Standardized Test Prep Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Carbon and Organic Compounds Table of Contents Section 1 Compounds of Carbon Section 2 Names and Structures of Organic Compounds Section 3 Organic Reactions Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Bellringer • Write a list of facts that you already know about carbon. • Draw the Lewis diagram for carbon. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Objectives • Explain the unique properties of carbon that make the formation of organic molecules possible. • Relate the structures of diamond, graphite, and other allotropes of carbon to their properties. • Describe the nature of the bonds formed by carbon in alkanes, alkenes, alkynes, aromatic compounds, and cyclic compounds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Objectives, continued • Classify organic compounds such as alcohols, esters, and ketones by their functional groups. • Explain how the structural difference between isomers is related to the difference in their properties. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Properties of Carbon • Carbon atoms nearly always form covalent bonds. • Three factors make carbon-carbon bonds unique: • First, carbon-carbon bonds are quite strong • Second, carbon compounds are not very reactive. • Third, carbon can form up to four single covalent bonds, so a wide variety of compounds is possible. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Properties of Carbon, continued Carbon Exists in Different Allotropes • As an element, carbon atoms can form different bonding arrangements, or allotropes. • The different allotropes have properties that differ due to the different arrangements of the carbon bonds. Other Carbon Allotropes Include Fullerenes and Nanotubes • Besides diamond and graphite, carbon allotropes include buckminsterfullerene, and nanotubes. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Allotropes of Carbon Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Comparing Allotropes of Carbon Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Organic Compounds • Organic compounds contain carbon, and most also contain atoms of hydrogen. • They can contain other elements, such as oxygen, nitrogen, sulfur, phosphorus, and the halogens. • Chemists group organic compounds with similar characteristics into classes. • The simplest class of organic compounds, hydrocarbons, contain only carbon and hydrogen. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Organic Compound Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Hydrocarbon Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Organic Compounds, continued Alkanes Are the Simplest Hydrocarbons • Alkanes are hydrocarbons with carbon atoms that are connected only by single bonds. • Three alkanes are methane, ethane, and propane. • The formulas of the alkanes fit the general formula CnH2n+2, where n is the number of carbon atoms. • For example, if an alkane has 30 carbon atoms, then its formula is C30H62. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Alkane Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Organic Compounds, continued Many Hydrocarbons Have Multiple Bonds • Alkenes are hydrocarbons that contain at least one double bond between two carbon atoms. • Alkenes with one double bond have a general formula that is written CnH2n. • Alkynes are hydrocarbons that contain at least one triple bond between two carbon atoms. • An alkyne with one triple bond is written as CnH2n−2. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Alkene Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Alkyne Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Organic Compounds, continued Carbon Atoms Can Form Rings • Carbon atoms that form covalent bonds with one another can be arranged in a straight line or in a branched arrangement. • Carbon bonds can also be arranged in a ring structure. • The prefix cyclo- is added to the name of an alkane to indicate that it has a ring structure. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Cycloalkane Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Organic Compounds, continued Benzene Is an Important Ring Compound • An important organic ring compound is the hydrocarbon benzene, C6H6. • Benzene is the simplest aromatic hydrocarbon. • It can be drawn as a ring with three double bonds. • Experiments show that all the carbon-carbon bonds in benzene are the same, so it is a molecule with resonance structures. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Benzene Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds • Other classes of organic compounds contain other atoms such as oxygen, nitrogen, sulfur, phosphorus, and the halogens along with carbon and hydrogen. • The word organic originally described only compounds made by living things. Now chemists can make organic compounds from inorganic substances. Many Compounds Contain Functional Groups • A typical organic compound has a group of atoms that is responsible for its chemical properties. • This a group of atoms is known as a functional group. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds, continued Many Compounds Contain Functional Groups, continued • Organic compounds are commonly classified by the functional groups they contain. • Because single bonds between carbon atoms rarely react, functional groups are often responsible for how an organic compound reacts. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Functional Group Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds, continued Comparing Classes of Organic Compounds Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds, continued Functional Groups Determine Properties • The presence of a functional group causes an organic compound to have properties that differ greatly from those of the corresponding hydrocarbon. • The structural formulas of butane and 1-butanol both have 4 carbon atoms joined by single bonds in a line. • Butane is a gas at room temperature, but 1-butanol is a liquid and has a greater density and higher melting and boiling points than butane. • The only difference between butane and 1-butanol is the presence of the functional group —OH on one of the carbon atoms in 1-butanol. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Classes of Organic Compounds Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds, continued Different Isomers Have Different Properties • Both molecules below are alcohols and have the same molecular formula: C4H10O. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 1 Compounds of Carbon Other Organic Compounds, continued Different Isomers Have Different Properties, continued • The molecules of 1-butanol and 2-methyl-1-propanol differ in the way in which their atoms are arranged. • Isomers are compounds that have the same formula but differ in their chemical and physical properties because of the difference in the arrangement of their atoms. • The greater the structural difference between two isomers, the more they will differ in their properties. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 19.1 Review, pg. 686 1. List the three factors that make the bonding of carbon atoms unique. Strong bonds exist between carbon atoms, carbon compounds have low reactivity, carbon can form a wide variety of compounds. 2. What are allotropes? Form of an element that differ in either structure or in bonding. 3. How are alkanes, alkenes, and alkynes similar? How are they different from each other? Alkanes –single bonds, alkenes-at least one double bond, alkynes- one or more triple bonds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 4. Draw the simplified representation of the resonance structure for benzene. 5. List four elements other than carbon and hydrogen that can bond to carbon in organic compounds. Oxygen, nitrogen, phosphorus, sulfur, and the halogens 6. What is an aromatic compound? A ring of carbon atoms that display resonance because of delocalized electrons that provide great stability. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 7. What is a functional group? Is an atom or a group of atoms that gives characteristic properties to organic compounds. 8. What is an isomer? What do two molecules that are isomers of each other have in common? One of two or more compounds that have the same chemical composition but different structures. Their chemical compositions Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 9. Draw a structural formula for the straight chain hydrocarbon with the molecular formula C3H6. Is this an alkane, alkene, or alkyne? 10. Can molecules with molecular formulasC4H10 and C4H10O be isomers of one another? Why or why not? No, they have different types of elements. 11. Draw a structural formula for an alkyne that contains seven carbon atoms. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 12. Draw the structural formulas for two isomers of C4H10. 13. Why is benzene not considered a cycloalkene even though double bonds exist between the carbon atoms that are arranged in a ring structure? It is an aromatic ring, and therefore has a completely different character from that of an alkene Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 14. Write the molecular formulas for an alkane,alkene, and alkyne with 5 carbon atoms each.Why are these three hydrocarbons not considered isomers? they have different chemical formulas 15. Draw C4H6 as a cycloalkene. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Bellringer • Examine the table on the next slide. • Determine what organizing principles you see that will help you quickly process all the information contained in the table. • Answer: Each formula beyond ethane contains one more —CH2— group. Beyond butane, the formulas are designated by their prefixes. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Bellringer, continued Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Objectives • Name simple hydrocarbons from their structural formulas. • Name branched hydrocarbons from their structural formulas. • Identify functional groups from a structural formula, and assign names to compounds containing functional groups. • Draw and interpret structural formulas and skeletal structures for common organic compounds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons • Inorganic carbon compounds are named by using a system of prefixes and suffixes. • Organic compounds have their own system of prefixes and suffixes that denote classes. • For example, the names of all alkanes end with the suffix -ane. • For alkanes that consist of five or more carbon atoms, the prefix comes from a Latin word that indicates the number of carbon atoms in the chain. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Naming Short-Chain Alkenes and Alkynes • A saturated hydrocarbon is one in which each carbon atom forms four single covalent bonds. • The alkanes are saturated hydrocarbons. • An unsaturated hydrocarbon is one in which not all carbon atoms have four single covalent bonds. • Alkenes and alkynes are unsaturated hydrocarbons. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Saturated Hydrocarbons Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Unsaturated Hydrocarbons Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Naming Short-Chain Alkenes and Alkynes, continued • The rules for naming an unsaturated hydrocarbon with fewer than four carbon atoms are similar to those for naming alkanes. • A two-carbon alkene is named ethene, with the suffix -ene indicating that the molecule is an alkene. • A three-carbon alkyne is named propyne, with the suffix –yne indicating that the molecule is an alkyne. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Naming Long-Chain Alkenes and Alkynes • The name for an unsaturated hydrocarbon containing four or more carbon atoms must indicate the position of the double or triple bond within the molecule. • First number the C atoms in the chain so that the first C atom in the double bond has the lowest number. • If there is more than one multiple bond in a molecule, number the position of each multiple bond, and use a prefix to indicate the number of multiple bonds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Naming Long-Chain Alkenes and Alkynes, continued • The molecules on the left is correctly numbered from left to right because the first carbon atom with the double bond must have the lowest number. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Straight-Chain Hydrocarbons, continued Naming Long-Chain Alkenes and Alkynes, continued • For example, the following molecule is called 1,3-pentadiene. • (Note the placement of the prefix di-.) Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons • When a hydrocarbon is not a simple straight chain, first count the carbon atoms in the longest chain. • The named is based on the corresponding alkane. The compound below has a “parent” chain that contains 7 carbon atoms, so it is heptane. • Next, number the C atoms so that any branches on the chain have the lowest numbers possible. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Using Prefixes to Name Organic Compounds Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Name the Attached Groups and Indicate Their Positions • The third carbon atom has a —CH3 group attached. This group is known as a methyl group. • Because the methyl group is attached to the third C, the complete name is 3-methylheptane. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Name the Attached Groups and Indicate Their Positions, continued • You can omit the numbers if there is no possibility of ambiguity. • For example, a propane chain can have a methyl group only on its second carbon. • If the methyl group were on the first or third carbon of propane, the molecule would be butane. • So, 2-methylpropane is called methylpropane. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Name the Attached Groups and Indicate Their Positions, continued • With unsaturated hydrocarbons that have attached groups, the longest chain containing the double bond is considered the parent compound. • In addition, if more than one group is attached to the longest chain, the position of attachment of each group is given. • Prefixes are used if the same group is attached more than once. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Name the Attached Groups and Indicate Their Positions, continued • The chain with the double bond has 5 C atoms, so the compound is a pentene. • The 1st C atom has a double bond, so it is 1-pentene. Two methyl groups are attached to the third carbon atom, so the name is 3,3-dimethyl-1-pentene. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Branched Hydrocarbon Sample Problem A Name the following hydrocarbon. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Branched Hydrocarbon, continued Sample Problem A Solution The triple bond makes the branched hydrocarbon an alkyne. Identify the longest continuous chain and name it. Number the parent chain so that the triple bond is attached to the C atom with the lowest number. Name the groups that make up the branches. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Branched Hydrocarbon, continued Sample Problem A Solution, continued Identify the positions that the branches occupy on the longest chain. The longest continuous chain has four carbon atoms. The parent chain is butyne. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Branched Hydrocarbon, continued Sample Problem A Solution, continued The numbering begins with the triple bond. Two methyl, —CH3, groups are present. Both methyl groups are attached to the third carbon atom. The name is: 3, 3-dimethyl-1-butyne. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Names of Compounds Reflect Functional Groups • Names for organic compounds with functional groups are based on the same system for branched chains. • First, the longest chain is named. • Then a prefix or suffix indicating the functional group is added to the hydrocarbon name. • When necessary, the position of the functional group is noted just as with hydrocarbon branches. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Naming Compounds with Functional Groups • A prefix or suffix can indicate a functional group. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming Branched Hydrocarbons, continued Names of Compounds Reflect Functional Groups, continued • Because the longest chain in the structure below has three C atoms, the name is based on propane. • The —OH functional group classifies it as an alcohol. • Because the —OH is attached to the second C atom, the correct name for this compound is 2-propanol. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Compound with a Functional Group Sample Problem B Name the following organic compound. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Compound with a Functional Group, continued Sample Problem B Solution The functional group indicates that this compound is a ketone. Identify the longest continuous chain and name it. Number the parent chain so that the functional group is attached to the C atom with the lowest number. Identify the position the functional group occupies on the longest chain, and name the organic compound. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Naming a Compound with a Functional Group, continued Sample Problem B Solution, continued The longest continuous chain has six carbon atoms: the parent chain is hexane. The carbon atoms are numbered from right to left to give the ketone functional group the lowest number. The name of this organic compound is 3-hexanone. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Representing Organic Molecules • There are many ways of depicting organic molecules. • Each type of model used to represent an organic compound has both advantages and disadvantages. • They can highlight different features such as the number and kinds of atoms or the three-dimensional shape of the space-filling model. • A model cannot fully show the true three-dimensional shape of a molecule or show the motion within a molecule caused by the atoms’ constant vibration. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Types of Molecular Models Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Structural Formula Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Representing Organic Molecules, continued Structural Formulas Can Be Simplified • Structural formulas are sometimes represented by skeletal structures, which show bonds, but leave out some or even all of the carbon and hydrogen atoms. • Skeletal structures usually show the carbon framework only as lines representing bonds. • These lines form a zigzag pattern to indicate the tetrahedral arrangement of bonds. • Atoms other than C and H are always shown. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Representing Organic Molecules, continued Structural Formulas Can Be Simplified, continued • In structural formulas, C and H atoms are not shown unless they are part of functional groups. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Drawing Structural and Skeletal Formulas Sample Problem C Draw both the structural formula and the skeletal structure for 1,2,3-propanetriol. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Drawing Structural and Skeletal Formulas, continued Sample Problem C Solution The name propanetriol indicates that the molecule is an alcohol that has three C atoms in the parent chain. The suffix -triol means that there are 2 alcohol groups. The 1,2,3- prefix indicates that an alcohol group is attached to the first, second, and third carbon atoms. Draw the carbon framework, and add the alcohol groups to the appropriate carbon atoms. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 2 Names and Structures of Organic Compounds Drawing Structural and Skeletal Formulas, continued Sample Problem C Solution, continued Add H atoms so that each C atom has 4 bonds. Show the carbon framework as a zigzag line. Include the functional groups as part of the structure. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Bellringer • Read the definitions of the key terms in this section and find a reaction that would illustrate each term. • Keep your definitions and check for correctness as you study this section. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Objectives • Describe and distinguish between substitution and addition reactions. • Describe and distinguish between condensation and elimination reactions. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions • Organic compounds participate in a variety of chemical reactions. • A substitution reaction is a reaction in which one or more atoms replace another atom or group of atoms in a molecule. • An addition reaction is a reaction in which an atom or molecule is added to an unsaturated molecule and increases the saturation of the molecule. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Halogens Often Replace Hydrogen Atoms • One substitution reaction occurs when a halogen, such as a chlorine atom, replaces a hydrogen atom on an alkane molecule, such as methane. • The substitution reactions can continue, replacing the remaining H atoms in methane one at a time. • The products are dichloromethane, trichloromethane, and tetrachloromethane (commonly known as chloroform). Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Substitution Reaction Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Hydrogenation Is a Common Addition Reaction • One addition reaction is hydrogenation, in which H atoms are added to an unsaturated molecule. • The product of the reaction contains fewer double or triple bonds than the reactant. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Addition Reaction Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Making Consumer Products by Hydrogenation • Another kind of hydrogenation is the manufacture of cyclohexane from benzene as shown below. • Over 90% of the cyclohexane that is made is used in the manufacture of nylon. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Some Addition Reactions Form Polymers • Some addition reactions involve joining smaller molecules together to make larger ones. • The smaller molecules are known as monomers. • The larger molecule that is made by the addition reaction is called a polymer. • Polyethylene is a strong but flexible plastic that is made from ethane monomers, C2H4. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Some Addition Reactions Form Polymers, continued • Because ethene is commonly known as ethylene, the polymer it forms is often called polyethylene. • The following equation shows how a portion of the polymer forms. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Substitution and Addition Reactions, continued Monomers Can Be Added in Different Ways • Polyethylene is a very long alkane polymer chain. • The chains form a product that is strong yet flexible. • Monomers can be added so that a chain branches. • For example, an ethene monomer is sometimes added to form a side chain. • A polymer with many side chains remain flexible. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. • Polyethylene is found in many ordinary household items, such as food wrap, shampoo bottles, milk containers, toys, and the common plastic bag used to tote groceries home from the store. •It is used to manufacture artificial knee and hip replacement parts, bulletproof vests, and even glassy flooring for ice skating rinks. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. •LDPE is an example of branched polyethylene since its carbon molecules are attached to long chains of polyethylene instead of hydrogen. • A linear structure of carbon to hydrogen occurs, which is known as high-density polyethylene (HDPE). Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Quick check Substitution and Addition Reactions 1. Explain why an addition reaction increases the saturation of a molecule. 2. What kind of organic reaction can form fluoromethane, CH3F, from methane? 3. Explain why alkanes do not undergo addition reactions. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. 4. Draw the skeletal structure of part of a polyethylene molecule consisting of eight monomers. 5. Can two different monomers be involved in an addition reaction? Why or why not? 6. Why does a substitution reaction involving an alkane and a halogen not increase the saturation of the organic compound? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Condensation and Elimination • Polymers can also be formed by a condensation reaction in which two molecules combine, usually accompanied by the loss of a water molecule. • The formation of water as a reaction product is the reason for the name of this type of reaction. • An elimination reaction is a reaction in which a simple molecule is removed from adjacent carbon atoms on the same organic molecule. • An elimination reaction also produces water. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Condensation and Elimination, continued Condensation Reactions Produce Nylon • Nylon is formed in a condensation reaction. • The reaction takes place between an amine group on hexanediamine and a carboxyl group on adipic acid. • A water molecule is eliminated when an H atom from the amine group and an —OH group from the carboxyl group are removed. • This reaction repeats, linking hundreds of reactants to form the synthetic polymer called nylon 66. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Condensation Polymers Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Condensation and Elimination, continued Many Polymers Form by Condensation Reactions • The polymer polyethylene terephthalate, abbreviated PET, is formed when two monomers are combined in the following condensation reaction. • The functional group present in the product shown above classifies this molecule as an ester, so PET is a polyester. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Section 3 Organic Reactions Condensation and Elimination, continued Elimination Reactions Often Form Water • An elimination reaction involves the removal of a small molecule from two adjacent carbon atoms. • The acid catalyzes a reaction that eliminates water from ethanol, which leaves a double bond. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Visual Concepts Elimination Reaction Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 1. Which of these formulas represents a saturated hydrocarbon? A. C2H2 B. C4H10 C. C5H10 D. C6H6 Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 1. Which of these formulas represents a saturated hydrocarbon? A. C2H2 B. C4H10 C. C5H10 D. C6H6 Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 2. Which of these is the product of the hydrogenation of benzene? F. benzyl hydride G. cyclohexane H. hexane I. 1-hexanol Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 2. Which of these is the product of the hydrogenation of benzene? F. benzyl hydride G. cyclohexane H. hexane I. 1-hexanol Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 3. Which of the following occurs during an addition reaction? A. The saturation of a molecule is increased. B. Single bonds are replaced by double bonds. C. A number of monomers react to form a polymer. D. One or more atoms replace another atom or group of atoms. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 3. Which of the following occurs during an addition reaction? A. The saturation of a molecule is increased. B. Single bonds are replaced by double bonds. C. A number of monomers react to form a polymer. D. One or more atoms replace another atom or group of atoms. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 4. Why is ethyne, also known as acetylene, used in welding torches instead of ethane which also has two carbon atoms? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 4. Why is ethyne, also known as acetylene, used in welding torches instead of ethane which also has two carbon atoms? Answer: Welding requires very high temperatures. The triple bond of acetylene releases much more energy than the single bond of ethane, creating a higher temperature flame. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 5. Why does a hydrogenation reaction never include an alkane as a reactant? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 5. Why does a hydrogenation reaction never include an alkane as a reactant? Answer: Because hydrogenation always includes a multiple bond. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 6. Sunflower oil contains polyunsaturated fat molecules. What does polyunsaturated mean? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Understanding Concepts 6. Sunflower oil contains polyunsaturated fat molecules. What does polyunsaturated mean? Answer: It has more than one double or triple carboncarbon bond. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Reading Skills Read the passage below. Then answer the questions. In the early part of the nineteenth century, chemists were unable to synthesize most carbon- containing compounds, unless they started with a material that had been produced by a living organism. The predominant theory was that there was a force inherent in living organisms that had to be used to make these compounds. In 1828 a German chemist, Friedrich Wöhler, succeeded in making an organic compound, urea, starting with inorganic chemicals. Although many chemists did not immediately accept that there was no living force involved in making organic molecules, the results prompted other scientists to perform experiments that led to synthesis of a variety of carbon compounds from inorganic sources and eventually new chemical theories. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Reading Skills 7. Why did Wöhler's synthesis of urea from inorganic compounds mean that the theory about organic materials had to be reevaluated? F. It showed that other chemists were wrong. G. It proved that urea is not an organic compound. H. New data was not consistent with the existing theory. I. There is no special force existant that organisms use to make compounds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Reading Skills 7. Why did Wöhler's synthesis of urea from inorganic compounds mean that the theory about organic materials had to be reevaluated? F. It showed that other chemists were wrong. G. It proved that urea is not an organic compound. H. New data was not consistent with the existing theory. I. There is no special force existant that organisms use to make compounds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Reading Skills 8. Why wasn't the theory that living organisms contributed special characteristics to organic compounds immediately replaced in the scientific community as soon as Wöhler announced his results? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Reading Skills 8. Why wasn't the theory that living organisms contributed special characteristics to organic compounds immediately replaced in the scientific community as soon as Wöhler announced his results? Answer: A single experiment from one laboratory is not always enough to convince everyone that the new data is valid and that the accepted theory is now disproven. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics Use the table below to answer questions 9 through 12. Comparing Classes of Organic Compounds Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 9. Which of the following statements is supported by the data in the table? A. The density of an organic molecule is primarily a function of the number of carbons it contains. B. A double bond between carbon and oxygen increases the boiling point more than a single bond. C. The increase in melting and boiling points of organic compounds is related to the polarity of functional groups. D. The increase in melting and boiling points of oxygencontaining organic molecules compared to hydrocarbons is primarily due to the polarity of the oxygen-hydrogen bond. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 9. Which of the following statements is supported by the data in the table? A. The density of an organic molecule is primarily a function of the number of carbons it contains. B. A double bond between carbon and oxygen increases the boiling point more than a single bond. C. The increase in melting and boiling points of organic compounds is related to the polarity of functional groups. D. The increase in melting and boiling points of oxygencontaining organic molecules compared to hydrocarbons is primarily due to the polarity of the oxygen-hydrogen bond. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 10. What is the main reason that the melting point of 2-butanone differs from that of butane? F. the loss of a hydrogen atom G. the increase in molecular size H. the increase in intermolecular forces I. the presence of oxygen in the molecule Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 10. What is the main reason that the melting point of 2-butanone differs from that of butane? F. the loss of a hydrogen atom G. the increase in molecular size H. the increase in intermolecular forces I. the presence of oxygen in the molecule Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 11. Identify two pairs of isomeric compounds in the table. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 11. Identify two pairs of isomeric compounds in the table. Answer: 1-butanol and diethyl ether; butanoic acid/2-butanone Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 12. In °C, by how much does the introduction of a hydroxyl group on the end carbon of the butane molecule increase the melting point? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 19 Standardized Test Preparation Interpreting Graphics 12. In °C, by how much does the introduction of a hydroxyl group on the end carbon of the butane molecule increase the melting point? Answer: 48.9 Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.