Final Exam Review

15)  Give chemical formulas for the following compounds:


a.  cobalt (II) acetate:
CO(C₂H₃O₂)2


b.  hydronitric acid:
H3N
c.  aluminum dichromate:
Al2(Cr2O7)3


d.  dinitrogen pentoxide:
N2O5


e.  cesium carbonate:
Cs2CO3


f.  magnesium chlorate:
Mg(ClO3)2


g.  lead (II) nitride:
Pb₃N₂


h.  acetic acid:
HCH3COO






31)  Think of a topic or question you think should have been covered


Like many, I had trouble with sig figs when working with pH and pOH, so I thought more clarification would be helpful.


pH=-log(H)
(H: morality)


#total sig figs morality= # sig figs AFTER decimal for pH and pOH




example:


pH=-log(.0228)
     = 1.642


-.0228 has 3 sig figs allowing the answer to have 3 sig figs AFTER the decimal


*the concept is applied to the reverse as well


H=10^-pH
   = 10^-4.82
   =1.5 x 10^-5 M


-The pH only has 2 sig figs AFTER the decimal => the molarity has a TOTAL of 2 sig figs


*The same rules apply to pOH