Determine the percent composition of nitrogen and oxygen with nitrogen dioxide, NO₂.

• A. 25.0% N and 75.0% O
• B. 15.5% N and 84.5% O
• C. 30.4% N and 69.6% O
• D. 69.6% N and 30.4% O

Answer: (C)

Verified step by step guidance

1. Calculate the molar mass of nitrogen dioxide (NO₂) by adding the atomic masses of nitrogen (N) and oxygen (O). The atomic mass of N is approximately 14.01 g/mol, and the atomic mass of O is approximately 16.00 g/mol. Since there are two oxygen atoms, the molar mass of NO₂ is calculated as: Molar mass of NO₂ = 14.01 g/mol (N) + 2 × 16.00 g/mol (O).
2. Determine the mass contribution of nitrogen in one mole of NO₂. Since there is one nitrogen atom in NO₂, the mass contribution of nitrogen is simply the atomic mass of nitrogen, which is 14.01 g/mol.
3. Calculate the percent composition of nitrogen in NO₂ by dividing the mass contribution of nitrogen by the molar mass of NO₂ and multiplying by 100 to convert it to a percentage: Percent composition of N = (Mass of N / Molar mass of NO₂) × 100.
4. Determine the mass contribution of oxygen in one mole of NO₂. Since there are two oxygen atoms, the mass contribution of oxygen is 2 × 16.00 g/mol.
5. Calculate the percent composition of oxygen in NO₂ by dividing the mass contribution of oxygen by the molar mass of NO₂ and multiplying by 100 to convert it to a percentage: Percent composition of O = (Mass of O / Molar mass of NO₂) × 100.