Final answer:
To find the moles of sulfur in 125 g of SO2, we calculate the molar mass of SO2 and use it to convert the mass of the sample to moles. Since SO2 contains one sulfur atom per molecule, the moles of sulfur will equal the moles of SO2, which is approximately 1.95 mol.
Step-by-step explanation:
To calculate the moles of sulfur (S) in 125 g of sulfur dioxide (SO2), we first need to determine the molar mass of SO2. The molar mass of sulfur is 32 g/mol and for oxygen, it is 16 g/mol. Since SO2 has one sulfur atom and two oxygen atoms, its molar mass is (1 × 32) + (2 × 16) = 64 g/mol.
Next, we convert the mass of SO2 to moles by dividing the mass of the sample by the molar mass of SO2:
125 g SO2 / 64 g/mol SO2 = 1.9531 mol SO2
Since there is one atom of sulfur in each molecule of SO2, the moles of sulfur will be the same as the moles of SO2:
1.9531 mol S (rounded to 1.95 mol for simplicity). So, the closest option to our calculation is b) 2.50 mol.