Answer Happy

Consider the following two conformations of 2,3-dimethylbutane. For each of these conformations, use the table below to determine the total energy cost associated with all torsional strain and steric strain. ENERGY COSTS FOR COMPARING THE RELATIVE ENERGY OF CONFORMATIONS Interaction Type of Strain Energy Cost (kJ/mol) H/H Eclipse Torsional strain 4 CH3/H Eclipsed Torsional strain 6 CH3 CH3 Eclipsed Torsional strain + steric 11 hindrance CH3 CH3 Gauche Steric hindrance 3.8 (a) H. H CH₂ CH₂ CH₂ CH₂ 3.8 kJ/mol x 4-15.2 kJ/mol (6 kJ/mol x2)+(11 kJ/mol x 3) = 45 kJ/mol 11 kJ/mol x 4-44 kJ/mol 3.8 kJ/mol x 3-11.4 kJ/mol
(a) H₂ H (b) CH₂ CH₂ CH₂ CH₂ 3.8 kJ/mol x 4 = 15.2 kJ/mol (6 kJ/mol x 2) + (11 kJ/mol x 3) = 45 kJ/mol 11 kJ/mol x 4 = 44 kJ/mol 3.8 kJ/mol x 3 = 11.4 kJ/mol CH₂ CH₂ H₂C. HCH₂ 3.8 kJ/mol x3 = 11.4 kJ/mol 6 kJ/mol + 11 kJ/mol = 17 kJ/mol (6 kJ/mol x 2) + 3.8 kJ/mol = 15.8 kJ/mol (6 kJ/mol x 2) + 11 kJ/mol = 23 kJ/mol