MDCAT Chemistry MCQ #443

A chemist analyzes a pure sample of propanal (C3H6O). What is the calculated percentage of oxygen by mass in this specific compound?

MDCAT Chemistry MCQ #443

  1. Question 1

    Q1. A chemist analyzes a pure sample of propanal (C3H6O). What is the calculated percentage of oxygen by mass in this specific compound?

    • A) 16.0%
    • B) 27.6%
    • C) 50.0%
    • D) 58.0%

    Answer: 27.6%

    Explanation: Propanal (58 g/mol) contains 16g of oxygen; (16/58)*100 equals 27.6%. 16.0% would imply a much larger molar mass.