Download Lab 2 for Molecular Models and Conformational Analysis | CHEM 341 and more Lab Reports Organic Chemistry in PDF only on Docsity! 1Chem 341 - Molecular Models, Copyright - D.J. Dyer & SIUC Molecular Models & Conformational Analysis Important Concepts • Organic Nomenclature • Drawing Chemical Structures • Conformational Analysis of Alkanes • Cis vs. Trans • Ring Structures Use molecular model kit to complete the worksheet in lab. 2Chem 341 - Molecular Models, Copyright - D.J. Dyer & SIUC - saturated hydrocarbons - C-C single bonds Alkanes Nomenclature (naming compounds) #Carbons 1 2 3 4 5 6 7 8 9 10 11 12 Name Methane Ethane Propane Butane Pentane Hexane Heptane Octane Nonane Decane Undecane Dodecane Structure CH4 CH3-CH3 CH3CH2CH3 CH3CH2CH2CH3 CH3CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH2CH3 CH3CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH3 Abbreviated Structure . Assume 3 Hydrogens Assume 2 Hydrogens 5Chem 341 - Molecular Models, Copyright - D.J. Dyer & SIUC Relative Energy of Conformations HH H H H H H H H H H H H H H H H H HH H H H H H H H H H H H H H H H H HH H H H H Rotate back 60o Clockwise Rotate back 60o Clockwise Rotate back 60o Clockwise Rotate back 60o Clockwise Rotate back 60o Clockwise Rotate back 60o Clockwise (a) (b) (c) (d) (e)(f)(g) a b c d e f g 0o 60o 120o 180o 240o 300o 360o En er gy Ethane What would energy diagram for n-butane look like? What would energy diagram for n-butane look like? 6Chem 341 - Molecular Models, Copyright - D.J. Dyer & SIUC Conformations of Cyclohexane 2D H H H H H HHH H H H H Dash-Wedge Chair † Photo Source: † The Comfort Store, ¶ Model Ships Online Boat ¶ ax eq ax eq X X Y Y Y Y XX Chair Flip 7Chem 341 - Molecular Models, Copyright - D.J. Dyer & SIUC Relative Energy of Cyclohexane Conformations Axial vs. Equatorial ax HH eq CH3 H3CH HEquatorial methyl is favored Cis vs. Trans X Y H H X H H Y= X H Y H One group is always equatorial cis Both groups are equatorial or axial X H H Y X H Y H= X H H Y trans
