Final answer:
To find the mass of anhydrous magnesium sulfate after heating magnesium sulfate heptahydrate, we can use the molar masses of both compounds to calculate that 76.2 g of the hydrated form will yield approximately 37.21 g of the anhydrous compound.
Step-by-step explanation:
To determine the mass of the anhydrous magnesium sulfate compound after heating magnesium sulfate heptahydrate to drive off all the water, we need to know the molar mass of magnesium sulfate heptahydrate (MgSO4·7H2O) and the molar mass of anhydrous magnesium sulfate (MgSO4).
MgSO4·7H2O has a molar mass of approximately 246.47 g/mol, and MgSO4 has a molar mass of approximately 120.36 g/mol. Subtracting the mass of the water (7 moles of H2O, approximately 126.11 g/mol) from magnesium sulfate heptahydrate gives us the mass of the anhydrous compound in one mole. Using these molar masses, we can calculate the mass of the anhydrous compound from the 76.2 g of magnesium sulfate heptahydrate that have been heated, as follows:
Mass of anhydrous magnesium sulfate = (mass of magnesium sulfate heptahydrate) × (molar mass of MgSO4) / (molar mass of MgSO4·7H2O)
Mass of anhydrous magnesium sulfate = 76.2 g × 120.36 g/mol / 246.47 g/mol
Mass of anhydrous magnesium sulfate = approximately 37.21 g
So, after heating the magnesium sulfate heptahydrate to remove all water and obtaining the anhydrous compound, the mass of the anhydrous magnesium sulfate would be approximately 37.21 g.