Molar mass of lead is 207.2 grams/mole (according to the periodic table)
Molar mass of Sulfate
Sulfur + 4 Oxygen
Molar mass of Sulfur + molar mass of 4 oxygen = 96 grams/mole for sulfate
207.2 + 96.6 = 303.8 grams/mole for Lead(II) Sulfate (I might be .5 grams of, down or up)