E X P E R I M E N T : MO L E C U L A R MO D E L I N G I :CO N F O R M A T I O NS AN A L YSIS &PR O P E R T I ESName _______________________________________ Instructor ____________________________________ Date ________________________________________ Laboratory Questions These questions are to be completed and turned in at the beginning of the pre-lab period. PR E- L A B Q U ES T I O NS1. Examine the diagram of conformational energies for butane shown in the McMurry textbook (Figure 3.9). Which conformation(s) would represent a local minimum and which would represent a global minimum? 2. McMurry indicates that the gauche conformation (60dihedral angle) of butane results in steric strain because of repulsion between the two methyl groups (p 96). a. Explain why the magnitude of this ster icstrain would decrease if the dihedral angle was increased from 60to 65b. How would the magnitude of this ster icstrain between these two gauche methyl groups change (increase or decrease?) if the C1-C2-C3(or C2-C3-C4) bond angle was increased to more than 109.5?
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