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Ch. 13 Hydrocarbons. Milbank High School. Objectives. 1. What is organic chemistry? In general, how do organic compounds differ from inorganic compounds? 2. Why are there so many more organic compounds than inorganic compounds?
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Ch. 13Hydrocarbons Milbank High School
Objectives 1. What is organic chemistry? In general, how do organic compounds differ from inorganic compounds? 2. Why are there so many more organic compounds than inorganic compounds? 3. What are hydrocarbons? What structural features identify alkanes? Alkenes? Alkynes? Aromatic hydrocarbons? 4. How are alkanes, alkenes, alkynes, and aromatic hydrocarbons named using IUPAC nomenclature? 5. What are the physical and chemical properties of alkanes, alkenes, alkynes, and aromatic hydrocarbons?
Objectives 6. What is an alkyl group? 7. What are some products from reactions of alkanes? How are they formed? 8. What are the major reactions of alkenes? What are the products of those reactions? 9. What are polymers? How are they formed and utilized? 10. What is petroleum and how is it utilized?
Organic Chemistry • Chemistry of compounds that contain carbon • Combine mainly with hydrogen, oxygen, and nitrogen • Over 10 million compounds made with these 4 elements • 95% of compounds contain carbon • Form stable, covalent bonds with each other
Organic (Benzene) Low melting pts Low boiling pts Low solubility in water Highly flammable Nonconductive Covalent bonds Inorganic (NaCl) High melting pts High boiling pts Soluble in water Nonflammable Conductive Ionic bonds Properties
Hydrocarbons • Compounds containing only two elements • Carbon and hydrogen
Sec. 13.1Alkanes: Structures and Names • Objectives • Identify an alkane • Determine what an isomer of an alkane is • Identify different types of alkanes
Alkanes • Saturated Hydrocarbons • Called saturated because each carbon is bonded to four other atoms • Only single bonds • Methane • Ethane • Propane
Homology • Related compounds • Homologs • Have properties that vary in a regular and predictable manner • A manner of organization • Similar to P.T.
Isomers • Different compounds having the same molecular formula • Butane • Isobutane (isolated branched chain)
Isomers • Pentane • Isopentane • Neopentane
Alkanes • CnH2n+2 • Representation • Structural Formulas • Condensed Structural Formulas • Butane
Alkyl Group • A group of atoms that results when one hydrogen atom is removed from an alkane • CnH2n+1 • Change –ane ending to –yl • Methyl • Ethyl • Propyl
Sec. 13.2IUPAC Nomenclature • Define IUPAC • Examine the rules for IUPAC naming • Determine the correct names of alkanes
IUPAC Nomenclature • Geneva, Switzerland 1892 • International Union of Pure and Applied Chemistry • IUPAC System of Nomenclature • (isobutane, isopentane are common names)
IUPAC Rules • 1. Name the longest chain in the parent compound. End in –ane. (Root name) • Number each carbon • See Example • 2. Note the alkyl groups attached • 3. Number the carbon that the group is attached to. • Must use the lowest number possible. • See Example
IUPAC Rules Con’t • 4. Use prefixes to indicate the amount of attached groups • See Example • 5. If there are more than two or more different substituents, list them in alphabetical order. If at equal points, lower alphabetical order given lowest number • See Example
IUPAC Rules Con’t • 6. Prefixes not included in alphabetizing • See Example
Name each of the following A. B. C. D.
Answers • a. 3-ethylhexane • 2,4-dimethylpentane • c. 3-methylhexane • d. 4-isopropylheptane
Draw the structural formulas for each of the following • 4-propylheptane • 3-ethyl-2-methylpentane • 3-isopropyl-3-methyloctane
Sec. 13.3Properties of Alkanes • Objectives • Determine the physical and physiological properties of alkanes
Physical Properties • Nonpolar • Insoluble in water • Less dense than water • Less than 1.0g/ml • Related to one another • See chart • Boiling points • Increase with higher molar mass
Physiological Properties • Gases serve as anesthetics • Liquid alkanes • Light liquids • Harmful to lungs • Heavy liquids • Mineral oil • Petroleum jelly
Sec. 13.4Chemical Properties: Reactions of Alkanes • Objectives • Determine the chemical properties of alkanes
Chemical Properties • Do not react with many laboratory agents • Usually very flammable • Undergo combustion reactions CH4 + 2 O2 CO2 + 2 H2O + Heat 2 CH4 + 3 O2 2 CO + 4 H2O (Harmful carbon monoxide reaction)
Sec. 13.5Halogenated Hydrocarbons • Objectives • Define what halogenated hydrocarbons are • Name halogenated hydrocarbons using common and IUPAC names
Halogenated Hydrocarbons • Have one or more hydrogen atoms replaced by halogen atoms • Usually these are formed under UV light or very high temps • Results in an alkyl halide
Common Names • First part of name is alkyl group • Second part is the halogen, ending in –ide • Name these: • CH3CH2Br • (CH3)2CHCl • CH3I • CH3CH2CH2F
Answers • Ethyl bromide • Isopropyl chloride • Methyl iodide • Propyl flouride
IUPAC Names • Rules similar to those used for naming alkanes • Substitute in the prefixes fluoro-, chloro-, bromo-, and iodo-
Answers • 2-chloropentane • 4-bromo-2-methylhexane • 2-chloro-3-methylbutane • 1-bromo-3-chloro-4-methylpentane
Sec. 13.6Cycloalkanes • Define what a cycloalkane is • Name and draw cycloalkanes
Cycloalkanes • Carbon atoms that are joined in a ring or circle • Simplest: cyclopropane • Another: cyclohexane
Naming • Add cyclo- • Otherwise fairly similar to regular naming • Draw structures for the following compounds • Cyclooctane • Ethylcyclohexane • 1,1,2-trimethylcyclobutane
Answers • A. • B. C.
Draw these structures • Cyclopentane • 1-ethyl-2-methylcyclopentane • 1-ethyl-1,2,5,5-tetramethylcycloheptane
Answers • A. • B. • C.
Sec. 13.7Alkenes • Objectives • Define alkene • Name alkenes using IUPAC rules
Alkenes • End in -ene • Unsaturated hydrocarbons • Have a double bond (CH3=CH2)
IUPAC Rules • Name the longest chain. • Indicate the position of the double bond with the lowest number possible. • Substituent groups named like alkanes 5-methyl-2-hexene
Answers • 6-dimethyl-2-heptene • 2-ethyl-1-butene • 4-ethyl-2-methyl-2-hexene • 1-methylcyclohexene • 2,4,4-trimethyl-2-pentene
Draw the structure for the following • 3,4-dimethyl-2-pentene • 3-ethyl-2-methyl-1-hexene • 3-isopropylcyclopentene
Answers • A. • B. • C.
Sec. 13.8Properties of Alkenes • Objectives • Determine the properties of alkenes
Properties of Alkenes • Similar to alkanes • Occur widely in nature • Ethylene • Triggers fruit ripening • Can be used artifically • Others • Carotene • Vitamin A • Fruit coloring