WAEC - Chemistry (2018 - No. 9)

An organic compound has the empirical formula \(CH_{2}\). If its molar mass is 42\(gmol^{-1}\), what is its molecular formula?  (C = 12.0, H = 1.0)
\(C_{2}H_{4}\)
\(C_{3}H_{4}\)
\(C_{3}H_{6}\)
\(C_{4}H_{8}\)

Explanation

Given the molecular formula, \(CH_{2}\).

The empirical formula will be \((CH_{2})n\)= 42

\((12+(2\times1))n =42\)

⇒ \(14n =42\)

n = 3, hence the empirical formula is \(C_{3}H_{6}\)

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