56 . B
57 . A
Twenty total electrons describes Ca. But it is an excited state calcium molecule, because the
3 d subshell is filled before the 4s subshell (usually the 4 s subshell is filled first, then the 3d
subshell). Those two electrons must have jumped from the 4s to the 3d subshell.58 . B
2.37 V – 1.03 V = +1.34 V; a spontaneous reaction. All of the other equations have negative
values.
59 . D
See the explanation to question 58.
60 . C
Remember that in resonance forms, only electrons (bonds and nonbonding electron pairs) can
move. If you examine the answer choices, you can see that the atomic linkages are all the
same except for answer choice C; the carbon second from the left in choice C now has a methyl
group bonded to it, whereas the other choices have hydrogens in this position.
61 . A
One equivalent of an acid is the amount of the acid that is able to furnish one mole of
hydrogen ion, so 1 mole of H 3 PO 4 will furnish 3 mol of H+ ions.
1 mol H 3 PO 4 /3eq = x/0.15eq0.05 mol H 3 PO 462 . C
This question asks you which generalization CANNOT be made about the phase change of a
pure substance from solid to liquid. When a phase change occurs, the internal energy of the