<p>General comments --- This exam was pretty f'ing hard. I read through the Princeton Review book about 3x, did all the problems after each lesson (and usually missed no more than 1 per section), and still left around 13 blank.</p>
<p>I'm pretty sure Sr has a lower second ion energy than Ca because it's lower on the periodic table, and ionization energy increases as you go from bottom to top, and left to right. Sr also has two valence electrons like Ca does.</p>
<p>Here are some I had trouble with:
18. Forms oxidation state of +4: ??? (omit)
19. When mixed with soap produces ppt: Ca?
21. Forms blue color when dissolved in sulfate: ??? (omit)</p>
<p>When H ion. energy is decreased from n=2 to n=1, a photon is emitted: True?
The p orbital only holds 2 valence: Definitely true
<p>XH3, X = Phosphorus?</p>
<p>To be a polar molecule the shape needs to be t. pyramidal (XH3)?</p>
<p>Balancing equations: Na2O2 + H20 etc. etc. Coeff of O2 = 1? (did in 15 sec)</p>
<p>Which one requires energy input: Formation of H2 gas from two H atoms?</p>
<p>Given [HAc] = 1.8x10^-5M, you can tell it's a weak acid?</p>
<p>What would you not use to measure titrations: balance</p>
<p>More to come.</p>