Question

empirical and molecular formula calculation
propene has an empirical formula of ch₂. what is its molecular formula if it has a molar mass of 42.09 g/mol?

Explanation:

Step1: Calculate empirical formula mass

Molar mass of C = 12.01 g/mol, molar mass of H = 1.008 g/mol.
$\text{Empirical formula mass} = 12.01 + 2\times1.008 = 14.026\ \text{g/mol}$

Step2: Find the scaling factor $n$

$n = \frac{\text{Molar mass of compound}}{\text{Empirical formula mass}}$
$n = \frac{42.09}{14.026} \approx 3$

Step3: Multiply empirical formula by $n$

Multiply each subscript in $\text{CH}_2$ by 3.

Answer:

$\text{C}_3\text{H}_6$