What is the approximate percentage by mass of oxygen in methanal, HCHO (C = 12, H = 1, O = 16)?
Correct answer C. 53.3%
Explanation
Molar mass of HCHO = 12 + 2 + 16 = 30 g mol⁻¹. Percentage of oxygen = (16 ÷ 30) × 100 ≈ 53.3%.
Answer checked How we write and check questions
Discussion