What is the percent by mass of sulfur in sulfur dioxide (SO_2)?

• A. 66.7%
• B. 33.3%
• C. 50.0%
• D. 25.0%

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of sulfur dioxide, which is \(SO_2\), meaning it contains 1 sulfur atom and 2 oxygen atoms.
2. Find the atomic masses of sulfur and oxygen from the periodic table: sulfur (S) has an atomic mass of approximately 32.07 g/mol, and oxygen (O) has an atomic mass of approximately 16.00 g/mol.
3. Calculate the molar mass of sulfur dioxide by adding the atomic mass of sulfur to twice the atomic mass of oxygen: \(Molar\ mass = 32.07 + 2 \times 16.00\) g/mol.
4. Determine the percent by mass of sulfur in \(SO_2\) using the formula: \(\%\ sulfur = \left( \frac{\text{mass of sulfur}}{\text{molar mass of } SO_2} \right) \times 100\).
5. Substitute the values into the formula and simplify to find the percent by mass of sulfur in sulfur dioxide.