© 1998-9 Rainer Glaser. All rights reserved.
The University of Missouri at Columbia
Chemistry 412 - Computational Organic Chemistry - FS99
on Relative Stability
The values for the following problems all can be found in the
CRC Handbook of Chemistry and Physics.
An online version is
accessible at MU.
The heats of combustion of ethanol and dimethylether are
1366.8 and 1460.4 kJ/mol, respectively. Which one is the more stable
structure? What is the energy difference in kcal/mol?
Propylene and Cyclopropane are structure isomers on the same potential
energy surface. Their heats of combustion are 2058.0 and 2091.3 kJ/mol,
respectively. Explain the difference.
Consider the heats for formation of 1-butene, cis-butene,
trans-butene and isobutene. The values are in random sequence
-20.8, -29.8, -33.3 and -37.5 kJ/mol in the liquid. Assign the correct
value to the isomers.
Consider the heats for formation of 1,2-, 2,3-, and 1,4-pentadiene (yes,
the numbers are correct). The values are in increasing value 105.7, 133.1
and 140.7 kJ/mol in the liquid. Assign the correct value to the