10. Predict the geometry of the following molecules using the VSEPR method: (a) HgBr2,
(b) N2O, (c) SCN– (arrangement of atoms is SCN). (9 points)
(Reference: Chang 10.11)
11. Describe the geometry around each of the three central atoms in the CH3COOH
1. Tetrahedral, four bonds, 109.5 degrees apart, sp3 hybridization
2. Trigonal planar, three bonds (one double, to O), sp2 hybridization
3. Bent (at about 109.4 with two lone pairs, sp3 hybridization
(Reference: Chang 10.13)
12. What is the relationship between the dipole momentand bond moment? How is it
possible to have bond moments and yet be nonpolar? (3 points)
1.The dipole moment can be thought of as the sum of the bond dipoles in a molecule. If you have a molecule that consists of only one bond, then the dipole moment will be the same as the bond dipole. Most molecules have a dipole moment owing to the uneven distribution of charges about the molecule.
2.Because those molecules are symmetrical. CO2 and CCl4 are examples. the dipole moments of each bond cancel.
(Reference: Chang 10.16)
13. Specify which hybrid orbitals are used by carbon atoms in the following species:
(b) CO2, (c) CN–. (6 points)
a. sp + p + p.
c. sp + p + p.
(Reference: Chang 10.37)
14. How many sigma bonds and pi bonds are there in each of the following
Molecules? (6 points)
|a.4 sigma bonds||
|b.5 sigma bonds and 1 pi bond||
|c.7 sigma bonds and 3 pi bonds|
(Reference: Chang 10.41)
15. Which of the following species is not likely to have a tetrahedral shape? (a) SiBr4 (b) NF4+, (c) SF4, (d) BeCl4–2, (e) BF4–, (f) AlCl4–(6 points)