Stoichiometry, Moles, and Molecular Weight

Problem:  How is the formula weight calculated from a chemical formula?
Answer:  Multiply the atomic weight of the element by its subscript and sum the masses.

For NaCl    1 x Cl =  35.45 amu
                   1 x Na = 22.99 amu
                                  58.44 amu

For NO₂     1 x N =                           14.01 amu
                   2 x O = 2 x 16.00 amu = 32.00 amu
                                                           46.01 amu