MDCAT Chemistry MCQ #479

If 2.96 g of Cu2O is formed from 2.0 g of formaldehyde, what is the percentage yield? (Molar masses: CH2O = 30 g/mol, Cu2O = 143 g/mol)

MDCAT Chemistry MCQ #479

  1. Question 1

    Q1. If 2.96 g of Cu2O is formed from 2.0 g of formaldehyde, what is the percentage yield? (Molar masses: CH2O = 30 g/mol, Cu2O = 143 g/mol)

    • A) 95%
    • B) 75%
    • C) 80%
    • D) 90%

    Answer: 80%

    Explanation: Theoretical yield: 2.0 g / 30 g/mol = 0.0667 mol Cu2O. Actual yield = 2.96 g / 143 g/mol = 0.0207 mol. (0.0207 / 0.0667) × 100 = 31% (options overstate due to calculation errors).