Question

determine the quantity of moles of propylene (c₃h₆) in 25.0 g of the substance.

Explanation:

Step1: Calculate molar mass of propylene

The molar mass of $C_3H_6$: Carbon ($C$) has an atomic - mass of approximately $12.01\ g/mol$ and hydrogen ($H$) has an atomic - mass of approximately $1.01\ g/mol$.
$M = 3\times12.01\ g/mol+6\times1.01\ g/mol=36.03\ g/mol + 6.06\ g/mol=42.09\ g/mol$

Step2: Use the mole formula

The formula for calculating the number of moles ($n$) is $n=\frac{m}{M}$, where $m$ is the mass and $M$ is the molar mass.
Given $m = 25.0\ g$ and $M = 42.09\ g/mol$, then $n=\frac{25.0\ g}{42.09\ g/mol}\approx0.594\ mol$

Answer:

$0.594\ mol$