Chapter 9, Problem 116IE

The molecule 2-butene, C4Hs, can undergo a geometric change called cis-t As discussed in the "Chemistry and Life" box on the chemistry of Vision, such transformations can be induced by light and are the key to human VIS10n.

a What is me hybridization at the two central carbon atoms of 2.butene?

b. The isomerization occurs by rotation about the central bond, With reference to Figure 9.29, explain why the Ir bond between the two central carbon atoms is destroyed halfr.ay through the rotation from cis- to trans-2-butene

c. Based on average bond enthalpies (Table 8.3Q), how much energy per molecule must be supplied to break the C-CTr bond?

d. What is the longest wavelength of light that will provide photons of sufficient energy to break the C-CW bond and cause the isomerization?

e. Is the wavelength in your answer to part (d) in the visible portion of the electromagnetic spectrum? Comment on the importance of this result for human vision