A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of...

JAMB 2003

A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.
[H = 1, C = 12, O = 16]

A. CH₂O
B. C₃H₆O₃
C. C₆H₁₂O₆
D. C₆H₁₂O₃

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Correct Answer: Option C

Explanation

C - 40% ; 40/12 = 3.33
H - 6.7% ; 6.7/1 = 6.7
O - 53.3% ; 53.3/16 = 3.33
C = 3.33/3.33 = 1
H = 6.7/3.33 = 2
O = 3.33/3.33 = 1
CH₂O
(CH₂O)_n = 180
(12 + 2 + 16)~_n = 180
30n = 180
n = 6
= C₆H₁₂O₆

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