(a) Exercise 3.2 from Exploring Chemistry: Optimize the geometries of vinyl alcohol (CH2CHOH, syn and anti) and acetaldehyde (CH3CHO, two rotational conformations) at the HF/3-21G level. Compare the energy difference between the lowest energy conformers of vinyl alcohol and acetaldehyde with the enthalpy differences from the NIST Chemistry Webbook

(b) Using the exercise shown below as a guide, compute the aromaticity of ONE of the following: benzene, pyrrole, furan or thiophene. Optimize the geometries and calculate the energies at the HF/3-21G and B3LYP/6-31G(d) levels of theory (you may also try a higher level of theory if your wish).