1. The problem statement, all variables and given/known data http://avogadro.chem.iastate.edu/CHEM332/332Fall06Exam5Key.pdf Please go to page 5. 2. Relevant equations No equations, just concepts. 3. The attempt at a solution I tried the first problem (A), and got the solution wrong. I thought I'd check the concepts before attempting any other problem and checking the solution. I thought that it was photochemically allowed, not thermally because from what I understood, an odd number of double bonds in the initial reactant and a trans product indicated a conrotatory ring closure using light. Obviously, I was wrong. Could you please explain how I should solve this and similar problems? Thank you.