10
QuizMultiple Choice

Percent Composition and Molecular Formula — Quiz

Question 10 • Chemistry

What is the percent by mass of carbon in cap c sub 10 cap h sub 14 cap n sub 2 ? Use percent Element is equal to total mass of element in compound over molar mass of compound times 100

Answer
A
8 point 7 1 percent
B
69 point 5 0 percent
C
74 point 0 2 percent
D
17 point 2 7 percent

Explanation

Carbon contributes 10 × 12.01 = 120.10 g/mol. The compound’s molar mass is 120.10 + (14 × 1.008) + (2 × 14.01) = 162.23 g/mol. Thus, the percent by mass of carbon is (120.10 ÷ 162.23) × 100 ≈ 74.02%, so the correct choice is 74.02 percent.

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