Final answer:
To find the mass of 1.25 moles of calcium sulfate, its formula mass (136.15 g/mol) is multiplied by 1.25 moles to get 170.19 grams.
Step-by-step explanation:
To calculate the mass of 1.25 moles of calcium sulfate (CaSO4), first we need to determine the formula mass of calcium sulfate. The molar masses of the elements Ca, S, and O are approximately 40.08 g/mol, 32.07 g/mol, and 16.00 g/mol, respectively. Calcium sulfate contains one calcium atom, one sulfur atom, and four oxygen atoms, so its formula mass is:
(1 × 40.08 g/mol) + (1 × 32.07 g/mol) + (4 × 16.00 g/mol) = 40.08 g/mol + 32.07 g/mol + 64.00 g/mol = 136.15 g/mol.
Now, you can use this molar mass to find the mass of 1.25 moles of calcium sulfate:
1.25 moles × 136.15 g/mol = 170.19 grams of CaSO4
Thus, the mass of 1.25 moles of calcium sulfate is 170.19 grams.