Sulfur trioxide can react with atmospheric water vapor to form sulfuric acid that falls as acid rain. Calculate the mass in grams of 3.65 × 10²⁰ molecules of sulfur trioxide. A) 6.06 × 10^-4 g B) 2.91 × 10^-2 g C) 4.85 × 10^-2 g D) 20.6 g E) 1650 g

Question

Quizplus · Accepted Answer

To calculate the mass of sulfur trioxide, we will use the Avogadro's number (6.022 × 10²³ molecules/mol) and the molar mass of sulfur trioxide (80.06 g/mol).

Mass of 1 molecule of sulfur trioxide = molar mass/Avogadro's number
= 80.06 g/mol ÷ 6.022 × 10²³ molecules/mol
= 1.331 × 10^-22 g

Mass of 3.65 × 10^21 molecules of sulfur trioxide = (mass of 1 molecule) x (number of molecules)
= 1.331 × 10^-22 g × 3.65 × 10^21 molecules
= 4.85 × 10^-1 g
= 0.485 g

Therefore, the mass of 3.65 × 10^21 molecules of sulfur trioxide is 0.485 g which is equal to 4.85 × 10^-12 g or 4.85 × 10^-9 mg. The closest option is C, which is 4.85 × 10^-12 g or 4.85 × 10^-9 mg.

Sulfur Trioxide Can React with Atmospheric Water Vapor to Form