Question

What is the mass percentage of carbon in urea? (Molar mass of urea = \(60\,\text{g mol}^{-1}\))

• A. \(28.0%\)
• B. \(20.0%\)
• C. \(26.67%\)
• D. \(46.67%\)

Hint:

Mass percentage is calculated using the formula: \(\frac{\text{Mass of element}}{\text{Molar mass of compound}} \times 100\).

Answer 1

The Correct Option is B

Step 1: Write molecular formula of urea.
Urea = \(\text{CO(NH}_2)_2\).
Step 2: Calculate mass of carbon.
Mass of carbon in one mole of urea = \(12\,\text{g}\).
Step 3: Calculate mass percentage.
\[ %\text{ of C} = \frac{12}{60} \times 100 = 20.0% \] Step 4: Conclusion.
Thus, the mass percentage of carbon in urea is \(20.0%\).