What is energy difference between staggered and eclipsed conformations of 2,2,3,3-tetramethylbutane?
Is it 2k/J/mol?
Interaction Energy Cost (kJ/mol)
H/H Eclipsed 4
CH3/H Eclipsed 6
CH3/CH3 Eclipsed 11
CH3/CH3 Gauche 3.8
To calculate the energy difference between staggered and eclipsed conformations of 2,2,3,3-tetramethylbutane, you need to consider the energy contributions from different kinds of interactions.
The given energy costs for different interactions are as follows:
- H/H Eclipsed: 4 kJ/mol
- CH3/H Eclipsed: 6 kJ/mol
- CH3/CH3 Eclipsed: 11 kJ/mol
- CH3/CH3 Gauche: 3.8 kJ/mol
In the staggered conformation, the substituents are arranged in a staggered manner, resulting in minimal steric interactions and lower energy. In the eclipsed conformation, the substituents are aligned directly with each other, leading to increased steric interactions and higher energy.
To calculate the energy difference, you need to compare the total energy of the eclipsed conformation with the total energy of the staggered conformation. The energy difference is the energy of the eclipsed conformation minus the energy of the staggered conformation.
As the specific conformation energy values are not provided, we cannot directly calculate the energy difference. However, we can estimate it using the given energy costs for various interactions.
For the eclipsed conformation, we sum up the energy costs of the interactions between all the pairs of atoms:
Total Eclipsed Energy = H/H Eclipsed + CH3/H Eclipsed + 2 * CH3/CH3 Eclipsed
For the staggered conformation, we assume minimal steric interactions and consider only the CH3/CH3 Gauche interaction because the H/H interaction is not affected:
Total Staggered Energy = CH3/CH3 Gauche
To estimate the energy difference, subtract the total staggered energy from the total eclipsed energy:
Energy Difference = Total Eclipsed Energy - Total Staggered Energy
Now, substituting the given energy costs into the equation, we get:
Energy Difference = (4 kJ/mol) + (6 kJ/mol) + 2 * (11 kJ/mol) - (3.8 kJ/mol)
Simplifying the calculation gives us the estimated energy difference between the two conformations of 2,2,3,3-tetramethylbutane.
Note: The actual energy difference may vary depending on the specific conformation and other factors. It is always best to refer to reliable sources or perform experimental measurements for precise values.