4. Some contact lens solutions use boric acid buffers to resist pH change. Over what pH range does boric acid have good buffering capacity? Show your work.

What are the answers to these questions

Which of the following alkenes is the most stable?

PHOTOSYNTHETIC PIGMENTS 1.6 0.7 Qy D 1.4 CH. 0.6 1.2 Soret 0.5 A N- 0.4 0.8 H COOCH3 0.3 0.6 phytyl bacteriochlorophyll a 0.2- 0.4 0.1 0.2 - 300 400 500 600 700 800 700 750 800 850 900 2 (nm) 2 (nm) Figure 4.7 Absorption (left) and fluorescence (right) spectra of bacteriochlorophyll a in diethyl ether. 5. Look at this figure from Blankenship's book, Molecular Mechanisms of Photosynthesis. You can see the structure for bacteriochlorophyll a, along with its absorption spectrum. a. What is the molecular shape around the labeled carbon atom? b. What is the hybridization around that same carbon? c. Based on this structure, would you expect this molecule to absorb light in the visible spectrum? Why or why not? Absorbance Fluorescence (Arbitrary units)