Ch. 8 & 9 chemical bonds, etc.                                         75 points                                               AP chemistry

In problems involving any calculation, show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

 1. Sketch the Lewis structure(s) of  ___.  [10 points]

a. SO3 -2

a. CH2F2

2.  Sketch the molecular shape of __; include the name of the shape of the molecule and its bond angle(s). [10 points]

a. ClF3

b.  PH3

3.  Is the below molecules polar or nonpolar ?  Justify / rationalize your answer.  [10 points]

a. BH3

b.  NH3

4. In regards to an aldehyde with a methyl group:  .  [15 points]

a.  Clearly identify all central atoms in the compound and what is / are the bond angles on each central atom ? 

b. Identify the hybrid orbital(s) needed in the central atoms in the compound, justify / rationalize your answer, and describe its formation.

c. Using valence bond theory, describe the covalent bonds in the compound, where you identify the atom and its atomic orbital and / or hybrid orbital that is involved in the chemical bonds in the compound.

5. Sketch and label the axis / signal in the photoelectron spectrum for Be versus B on the same graph.  Justify / rationalize the relative signal size and relative position of each signal with respect to the horizontal axis.  [20 points]

6. old topics:  The amino acid glycine (gly) and alanine (ala) has a hydrogen and methyl group, respectively, as their side chain.  Draw the structural formula of a tripeptide, whose primary structure is ala – gly – gly, where alanine is the carboxyl end of the peptide.  Identify the peptide bond(s).  [10 points]