Meowthteam Meowthteam 08-10-2019 Chemistry contestada What is the formula mass of calcium sulfate dihydrate [CaSO4⋅2H2O]? Be sure to add the water of hydration, which is the 2H2O part (water surrounding the calcium sulfate). 136 g/mol 154 g/mol 164 g/mol 172 g/mol 172 is correct