Answer:
To determine the percent composition by mass of sulfur in the compound MgSO4, we need to first determine the molecular weight of sulfur in this compound. The molecular weight of a compound is the sum of the atomic weights of all of the atoms in the compound. In the case of MgSO4, the molecular weight is equal to the sum of the atomic weight of magnesium, the atomic weight of sulfur, the atomic weight of oxygen, and the atomic weight of oxygen.
The atomic weight of magnesium is 24.31 grams per mole, the atomic weight of sulfur is 32.06 grams per mole, and the atomic weight of oxygen is 15.999 grams per mole. Therefore, the molecular weight of MgSO4 is equal to 24.31 + 32.06 + 15.999 + 15.999 = 98.369 grams per mole.
To determine the percent composition by mass of sulfur in this compound, we need to divide the molecular weight of sulfur in the compound by the molecular weight of the compound, and then multiply by 100%. In this case, the molecular weight of sulfur in the compound is 32.06 grams per mole, and the molecular weight of the compound is 98.369 grams per mole. Therefore, the percent composition by mass of sulfur in MgSO4 is equal to (32.06 / 98.369) * 100% = 32.5%.
This means that 32.5% of the mass of MgSO4 is due to the sulfur atoms in the compound. The remaining 67.5% of the mass is due to the magnesium, oxygen, and sulfur atoms.