To calculate the mass of 0.150 mol sodium sulfate (Na2SO4), we need to know its molar mass. The molar mass of Na2SO4 is 142.04 g/mol.

Now, we can calculate the mass of 0.150 mol sodium sulfate using the formula:

Mass = Molar mass × Number of moles

Mass = 142.04 g/mol × 0.150 mol

Mass = 21.31 g

Therefore, the mass of 0.150 mol sodium sulfate is 21.31 grams.