How would you determine the formula weight of Naci? A) Add the mass of sodium (22.99 amu) plus the mass of chlorine together (35.45 amu). B) Multiply the mass of sodium (22.99 amu) by the mass of chlorine (35.45 amu). C) Divide the mass of chlorine (35.45 amu) by the mass by sodium (22.99 amu). D) Subtract the mass of chlorine (35.45 amu) from the mass of sodium (22.99 amu).