Answer
(a) 197.01 u
(b) 283.79 u
(c) 221.03 u
Work Step by Step
(a) Molecular weight ($C_6H_6Cl_2O_3$):
12.01* 6 + 1.008* 6 + 35.45* 2 + 16.00* 3 = 197.01 u
(b) Molecular weight ($C_{15}H_{22}ClNO_2$):
12.01* 15 + 1.008* 22 + 35.45* 1 + 14.01* 1 + 16* 2 = 283.79 u
(c) Molecular weight ($C_8H_6Cl_2O_3$):
12.01* 8 + 1.008* 6 + 35.45* 2 + 16* 3 = 221.03 u
