Chapter Twelve Saturated Hydrocarbons

Chapter 12 | Slide 2 of 64 Saturated Hydrocarbons cont’d © Bill Ross/CORBIS  CO 12.1

Chapter 12 | Slide 3 of 64 ←Fig Sheer numbers is one reason why organic chemistry is a separate field of chemical study. Saturated Hydrocarbons cont’d

Chapter 12 | Slide 4 of 64 Organic Chemistry The study of compounds containing ___________. There are many more organic compounds than inorganic compounds. Why?

Chapter 12 | Slide 5 of 64 Properties of Organic Compounds Typical organic compounds, Contain _____________ Have ____________bonds Have low ____________________________ –The bigger the molecule, _______________________________ Have low ______________________ –The bigger the molecule, _______________________________ Are _______________ Are soluble in ______________________ Have a ______________ than water

Chapter 12 | Slide 6 of 64 The Bonding of Carbon To understand the bonding patterns of carbon, we must review what we know about carbon –Does carbon tend to form ionic or covalent compounds?. –How many valence electrons does carbon have?. –How many electrons does carbon need to have an octet of electrons in its valence shell?.

Chapter 12 | Slide 7 of 64 Filling the Octet Carbon’s octet is filled when: –.

Chapter 12 | Slide 8 of 64 Chemical Bonding of Carbon Carbon bonds in a ___________: Wedges: ___________________. Dashed lines: ________________ __________. C

Chapter 12 | Slide 9 of 64 Learning Check Complete the structure by adding the correct number of hydrogen atoms. Identify the molecular shape around each of the carbon atoms. C-C-C C=C-C C=C=C

Chapter 12 | Slide 10 of 64 Learning Check Complete the structure by adding the correct number of hydrogen atoms. Identify the molecular shape around each of the carbon atoms.

Chapter 12 | Slide 11 of 64 Representations of Organic Compounds Chemical Formulas show: Expanded structural formulas show: Condensed structural formulas show: Line drawings:

Chapter 12 | Slide 12 of 64 Converting Between Structural, Condensed, and Line Formulas

Chapter 12 | Slide 13 of 64 Learning Check Convert the following structural formulas to condensed structural formulas and line drawings.

Chapter 12 | Slide 14 of 64 Learning Check Convert the following line drawings to condensed structural formulas and complete structural formulas

Chapter 12 | Slide 15 of 64 Saturated v. Unsaturated Saturated Organic Compounds –. Unsaturated Organic Compounds –. Which compounds on the previous learning checks represent saturated organic compounds? Unsaturated organic compounds?

Chapter 12 | Slide 16 of 64 Learning Check Which are saturated organic compounds, which are unsaturated organic compounds?

Chapter 12 | Slide 17 of 64 ←Fig Molecular structures of (a) methane, (b) ethane, and (c) propane, the three simplest alkanes.

Chapter 12 | Slide 18 of 64 Fig Models of (a) pentane, (b) isopentane, and (c) neopentane.

Chapter 12 | Slide 19 of 64 Alkanes Saturated hydrocarbons –Contain only __________________________ –. –All carbon-carbon bonds are ____________________ Determine the chemical formulas for the alkanes containing 3, 5, 7, and 9 carbons (separately) What is the relationship between the number of carbons and the number of hydrogens in these alkanes? –.

Chapter 12 | Slide 20 of 64 Fig Terms for organic compounds.

Chapter 12 | Slide 21 of 64 Alkanes with four or more carbons can be drawn and can exist in more than one configuration: Structural isomers – –The properties of compounds depend on ____________________________________________ C 4 H 10 Isomers

Chapter 12 | Slide 22 of 64 Table 12.1 Selected Physical Properties of C4 and C5 Alkanes.

Chapter 12 | Slide 23 of 64 Conformations of Alkanes Single bonds are not locked in place. There is rotation around single bonds. As a result, alkanes exist in different conformations. –Conformation: –Different conformations of the same molecule have the same condensed structural formula –Show some examples:

Chapter 12 | Slide 24 of 64 Conformations of the Same Molecule or Different Molecules?

Chapter 12 | Slide 25 of 64 What are the two isomers of C 2 H 6 O? C H H H C H H OHC H H HO C H H H C H H H C H OH HC H H H C H H HO

Chapter 12 | Slide 26 of 64 Structural Isomers How many structural isomers can you draw for hexane?

Chapter 12 | Slide 27 of 64 The number of carbon atoms attached to a branched carbon are designated by: –Primary: –Secondary: –Tertiary: –Quaternary:

Chapter 12 | Slide 28 of 64 C H H H R C H R H R C R R H R C R R R R primary (R represents a general alkyl group.) secondary tertiary quaternary

Chapter 12 | Slide 29 of 64 Naming Alkanes We will use the IUPAC system (International Union of Pure and Applied Chemistry). –In this system, we name both the ____________ and any ___________________ on the chain Parent chain: Substituents: –Alkyl groups –Halogen groups

Chapter 12 | Slide 30 of 64 Naming the Parent Chain Depends on the length of the chain –1 carbon: __________: CH 3 –2 carbons: _________ : CH 3 CH 3 –3 carbons: _________ : CH 3 CH 2 CH 3 –4 carbons: _________ : CH 3 CH 2 CH 2 CH 3 –5 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 3 –6 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 –7 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 –8 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 –9 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 –10 carbons: _________ : CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3

Chapter 12 | Slide 31 of 64 Learning Check A. What is the condensed formula for: H H H H H C C C C H H H H H B. What is its molecular formula? C. What is its name?

Chapter 12 | Slide 32 of 64 Step 1: –Find the longest continuous carbon chain: The longest chain is the parent. CH 3 CH 2 CCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CHCH 3

Chapter 12 | Slide 33 of 64 Step 2: –Number the carbon atoms in the main chain beginning at the end near the first branch point. CH 3 CH 2 CCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CHCH 3

Chapter 12 | Slide 34 of 64 AlkaneNameAlkyl GroupName CH 4 Methane CH 3 Methyl CH 3 Ethane CH 2 CH 3 Ethyl CH 3 CH 2 CH 3 Propane CH 2 CH 2 CH 3 CH 3 CHCH 3 Propyl Isopropyl Step 3: –Identify and number the substituents. –Alkyl groups: occur when a hydrogen atom is removed from an alkane. Replace “ane” with “yl”.

Chapter 12 | Slide 35 of 64 Fig The four most common branched-chain alkyl groups and their IUPAC names. Naming Substituents

Chapter 12 | Slide 36 of 64 Step 3: –Identify and number the substituents. –Use di, tri, tetra to name two like groups in an organic molecule. CH 3 CH 2 CCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CHCH 3

Chapter 12 | Slide 37 of 64 Step 4: –Name the alkane as one word. Note: if two or more side chains, write in alphabetical order. CH 3 CH 2 CCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CHCH 3

Chapter 12 | Slide 38 of 64 Step 4: –Name the alkane as one word. Note: if two or more side chains, write in alphabetical order. CH 3 CH 2 CCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 2 CHCH Parts: heptane 3,3-diethyl 4-methyl

Chapter 12 | Slide 39 of 64 Naming Conventions Carbons are numbered so the substituents get _____________________________ Substituents are named ________________ Numbers are separated from each other by _______________ Numbers are separated from letters by __________________ There are _____________ in the name

Chapter 12 | Slide 40 of 64 Name this alkane. CH 3 CH 2 CH 2 C CHCH 3 CH 3 Longest chain? Number the chain. Substituents? Name the alkane.

Chapter 12 | Slide 41 of 64 Name this alkane. CH 3 CHCH 2 CCH 3 CH 2 CH 2 CH 3 CH 3 Longest chain? Number the chain. Substituents? Name the alkane CH 3

Chapter 12 | Slide 42 of 64 Name this alkane. CH 3 CH 2 CHCH 2 CHCH 3 CH 2 CH 3 CH 3 Longest chain? Number the chain. Substituents? Name the alkane

Chapter 12 | Slide 43 of 64 Name this alkane. CH 3 CH 2 CH 2 CH 2 C CHCH 2 CH 3 CH 2 CH 3 CH 3 CH 2 CH 3 Longest chain? Number the chain. Substituents? Name the Alkane

Chapter 12 | Slide 44 of 64 Draw the alkane. 2-methylheptane 4-ethyl-3,4-dimethyloctane

Chapter 12 | Slide 45 of 64 Draw the alkane. 2,3-dimethylhexane 4-ethyl-2,4-dimethylhexane

Chapter 12 | Slide 46 of 64 Cycloalkanes Saturated hydrocarbons in which ______________ _________________________________________ Draw the structural formulas for the cycloalkanes with 4, 6, and 8 carbons. What is the relationship between the number of carbons and the number of hydrogens in a cycloalkane? –.

Chapter 12 | Slide 47 of 64 Cycloalkanes Properties: –. cyclopropane cyclobutane cyclopentane cyclohexane

Chapter 12 | Slide 48 of 64 Fig Simple cycloalkanes

Chapter 12 | Slide 49 of 64 Naming: –Count the carbons and add the prefix __________ –For substituted cycloalkanes, start at point of attachment and number around the ring to give any other substituent the ____________________. –_______________________ has priority. CH 2 CH 3 CH 3

Chapter 12 | Slide 50 of 64 CH 2 CH 2 CH 3 CH 3 Name this compound.

Chapter 12 | Slide 51 of 64 Learning Check

Chapter 12 | Slide 52 of 64 Isomerism in Cycloalkanes Cis-trans isomers: –Isomers that have the same molecular and structural formulas but different ______________ ________________________________________ ________________________________________ Cis isomer: Trans isomer:

Chapter 12 | Slide 53 of 64 cis (same)trans (opposite) trans-1,2-dimethylcyclopropane cis-1,2-dimethylcyclopropane Can also draw as:

Chapter 12 | Slide 54 of 64 Learning Check Determine whether cis-trans isomerism is possible for each of the following cycloalkanes. If so, then draw structural formulas for the cis and trans isomers –A. 1-ethyl-1-methylcyclopentane –B. Ethylcyclohexane –C. 1,4-dimethylcyclohexane –D. 1,1-dimethylcyclooctane

Chapter 12 | Slide 55 of 64 Chemical Reactions of Alkanes, I Combustion In combustion reactions, Alkanes react with _____________. _________________________ are produced. Alkane + O 2 

Chapter 12 | Slide 56 of 64 Chemical Reactions of Alkanes, II Halogenation –. –In halogenation reactions, –Requires _________________ –Reaction:

Chapter 12 | Slide 57 of 64 Figure In an alkane substitution reaction, an incoming atom or group of atoms (represented by the orange sphere) replaces a hydrogen atom in the alkane model.

Chapter 12 | Slide 58 of 64 An alkane in which one or more H atoms is replaced with a halogen (F, Cl, Br, or I) CH 3 Br Br CH 3 CH 2 CHCH 3 Cl Haloalkanes

Chapter 12 | Slide 59 of 64 Name the following: Learning Check

Chapter 12 | Slide 60 of 64 List other attached atoms or group ___________ ___________________ Br = bromo, Cl = chloro Cl Br CH 3 CHCH 2 CHCH 2 CH 2 CH 3 Substituents

Chapter 12 | Slide 61 of 64 The name of this compound is: Cl CH 3 CH 3 CH 2 CHCH 2 CHCH 3 1) 2,4-dimethylhexane 2) 3-chloro-5-methylhexane 3) 4-chloro-2-methylhexane Learning Check

Chapter 12 | Slide 62 of 64 Table 12.4 Saturated Hydrocarbons cont’d

Chapter 12 | Slide 63 of 64 Fig Models of four ethyl halides. Saturated Hydrocarbons cont’d

Chapter 12 | Slide 64 of 64 CAG 12.1