Final answer:
The formula weight of PbCl2 is 278.1 g/mol.
Step-by-step explanation:
The formula weight of PbCl2 can be calculated by adding the atomic weights of lead (Pb) and chlorine (Cl) using the subscript 2 to indicate that there are 2 chlorine atoms:
Formula Weight PbCl2 = atomic weight of Pb + (2 x atomic weight of Cl)
Using the atomic weights of Pb (207.2 g/mol) and Cl (35.45 g/mol), the calculation would be:
Formula Weight PbCl2 = 207.2 g/mol + (2 x 35.45 g/mol) = 207.2 g/mol + 70.9 g/mol = 278.1 g/mol