Ch. 8 & 9  chemical bonds                 test      [90 points]                               AP Chem


For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.  Clearly identify the problems done and do them in sequence and your answer must begin and end on the same page of paper; otherwise, you may lose points.



Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.


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1.   Is ___ a polar or nonpolar molecule ?  justify your response.  [20 points]


a.  ether with methyl group(s)


b.  alcohol with methyl group(s)


c.  selenium tetrafluoride


d.  boron trichloride


2.  Draw all Lewis structure(s) for __.  [15 points]


a.  carbonate ion

b.  bromine trifluoride

c.  PO2 ion


3.  Draw the molecular shapes of  ___;  name of the molecule’s shape & bond angle(s).  [15 points]


a.  carbonate ion

b.  bromine trifluoride

c.  PO2 ion


4.  Pick the “best” Lewis structure for SiO2; justify your choice.  [15 points]


5.  Apply valence bond theory to carbonate ion   [25 points]


a.  in regards to the hybrid orbital in the central atom

i.  identify it 

ii.  justify the need for a hybrid orbital

iii.  justify the need for that specific hybrid orbital


b.  describe the formation of that hybrid orbital starting from the atom’s orbital diagram


c.  describe the bonds in the ion