Organic Part 2 Hydrocarbons 1 Alkanes all single bonds 2 Alkenes C C saturated v unsaturated structural isomers geometric isomers 3 Alkynes C C 4 Aromatic hydrocarbons Reactivity of hydrocarbons addition reactions combustion reactions Petroleum Mary J Bojan Chem 110 1 Hydrocarbons This is the structure of 4 ethyl 2 3 3 trimethylnonane What is the molecular formula of this compound How many CH3 groups are there on this compound Mary J Bojan Chem 110 2 HYDROCARBONS Simplest organic compounds Contain only C and H Alkanes Alkenes Alkynes Aromatic Mary J Bojan saturated have the maximum number of H attached to the C skeleton unsaturated have double or triple bonds Chem 110 3 ALKENES Contain one or more double bonds C CnH2n C The C C H or C C C angle is 120 H H C H H H C C H H ethene ethylene C CH 3 propene Rotation about double bond is restricted Mary J Bojan Chem 110 4 Butene C 4H 8 There are several possible structures for a chain of 4 carbons with one double bond 1 butene 2 methylpropene 2 butene cis 2 butene Mary J Bojan trans 2 butene Chem 110 5 Structural vs Geometric Structural isomers same molecular formula different structure 1 butene 2 methylpropene 2 butene Geometric isomers same molecular formula different geometry cis 2 butene trans 2 butene cis isomer trans isomer Mary J Bojan same side opposite side across Chem 110 6 ALKYNES CnH2n 2 Contain C C H C C H ethyne acetylene CH3 C C H propyne bond angle is 180 H H H C C H H H C C H H C H C C H 1 butyne C H H 2 butyne structural isomers no geometric isomers are possible Mary J Bojan Chem 110 7 Reactions of Alkenes and Alkynes Addition reaction Double and triple bonds are reactive addition reactions typically occur at room temperature For Alkenes or CH3 CH CH2 Br2 CH3 CH CH CH3 HX where X Cl Br I OH etc For Alkynes CH3 C CH 2Br2 CH3 C C CH3 2HCl Mary J Bojan Chem 110 8 Aromatic Hydrocarbons Contain alternating single and double C C Bonds Benzene is prototypical molecule H H H C C C C H C C H H H H H C C C C C C H H H Usually written Aromatic hydrocarbons are less reactive than alkenes Special kind of bonding Have delocalized electrons Results in added stability Mary J Bojan Chem 110 9 Reactivity of Hydrocarbons Same reaction hydrocarbon Colorless Br2 red ALKANE Heptane Br2 ALKENE and ALKYNES 2 pentene Br2 AROMATIC toluene Br2 CH3 Mary J Bojan Chem 110 10 Functional Group classes Contain a representative group of elements in a fixed pattern Have similarities in structure and function reactivity Seemingly small changes in structure can have big affect on molecular properties Example adding an oxygen changes a hydrocarbon into an alcohol or an ether Mary J Bojan Functional Group Type hydrocarbon CH3 CH2 H ethane gas bp 89 C Chem 110 alcohol ether CH3 CH2 O H CH3 O CH3 ethanol di methyl ethe r liquid gas bp 78 C bp 24 C water soluble 11 Functional Group Classes Contain a representative group of elements in a fixed pattern Each class has similarities in structure and function reactivity Alcohols R OH R H Groups which have a carbonyl R alkyl group Ethers R O R R R H Aldehydes Amines H N H H N R R N R R R R C Ketones O O C C H R R Carboxylic Acid R R H R Ester Amide O O O C C C R Mary J Bojan O Chem 110 OH R OR R NHR 12 Functional Groups with O and N Alcohols R OH hydroxyl group hydrocarbon alkyl group Ether R O R Amines H N H H N R R N R R R R Mary J Bojan Chem 110 13 Functional Groups Containing the carbonyl group C O O Aldehyde C R H O Ketone C R R O Carboxylic Acids Mary J Bojan COOH Chem 110 C R OH 14 Organic Acids and Bases AMINES weak bases organic bases like NH3 CH3 3N aq H aq CH3 3NH aq CARBOXYLIC ACIDS weak acids organic acids R R C O aq HO Mary J Bojan C O aq H aq O Chem 110 15 Questions Which of the following hydrocarbon classes does NOT have a double or triple bond 1 2 3 4 alkane alkene alkyne aromatic Which one of the following functional group classes does not have a double bond 1 2 3 5 Mary J Bojan aldehyde Ketone amine ester Chem 110 16 The presence and properties of functional groups are responsible for the action of drugs What functional groups are present in these molecules O C H OH O C HO C CH 3 O CH3 O Acetaminophen Acetyl salicylic acid H3C Ibuprofen N O CH3 OH CH3 Mary J Bojan Chem 110 17 What s Next Formulas tell us how atoms are connected to each other Lewis structures tell us where the electrons are QUESTIONS What are the shapes of these molecules Can we use information about bonding connectivity of atoms molecular formulas etc to predict the shapes and properties of molecules Mary J Bojan Chem 110 18
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