A-Values
Now that we know how to calculate the difference in flip energy, we can plug that information into the famous Equilibrium Constant equation to determine exact Ke of the reaction.
Calculating Chair Equilibrium

Gas Constant correct number:8.314
Once we have the Ke of the equilibria, we can solve for x, which will be the percentage of my most favored chair.

Estimate the equilibrium composition of the chair conformers of cis-1,3-diethylcyclohexane at room temperature.
Did you remember to use the correct Gas Constant number?! (8.314)

Estimate the equilibrium composition of the chair conformers of trans-1-methyl-3-phenylcyclohexane at room temperature.

Note: The correct value for methyl should be 7.6, not 4.2
With that, the correct answer should be closer to 88% / 12% for the percentage of both chairs using the correct value for R (8.314). Hope that makes sense!
Do you want more practice?
- Using the data obtained in Problem 85, calculate the amount of steric strain in each of the chair conformers o...
- Using the data obtained in Problem 81, calculate the percentage of molecules of trans-1,2-dimethylcyclohexane ...
- (••) The A value of a substituent on a cyclohexane ring is essentially the ∆G° for a substituent going from th...
- (••) The A value of a substituent on a cyclohexane ring is essentially the ∆G° for a substituent going from th...
- (••) The A value of a substituent on a cyclohexane ring is essentially the ∆G° for a substituent going from th...