4. Using the results of Problem 3, verify that the dipole moment of the entire water molecule is 1.85 D, as was claimed before in the chapter. That is, if the bond moment of the preceding problem is represented by uB, what is the vector sum of two vectors of length uB that make an angle of 105 degrees to one another?

5. If the N-H bond in ammonia is 27% ionic, and the bond length is 1.01 A, what is the bond moment of each N-H bond?

6. With the value calculated in Problem 5, show that the observed dipole moment of ammonia should be 1.47 D. That is, what is the vector sum of three vectors of length uB that make angles of 107 degrees with one another? (There is more geometry than chemistry in this problem. )