# How many moles are there in 1.5 g of ethanol, CH_3CH_2OH?

Nov 10, 2015

$3.242459724759267 m o l$

#### Explanation:

Use the formula
$n = \frac{m}{M}$
where $n$ is the amount in moles ($m o l$), $m$ is the mass in grams ($g$), and $M$ is the molar mass in grams per mole ($g m o {l}^{-} 1$).

To find the molar mass of ethanol:
There are 2 $C$ atoms (molar mass $12.011 g m o {l}^{-} 1$),
6 $H$ atoms (molar mass $1.008 g m o {l}^{-} 1$),
and 1 $O$ atom (molar mass $15.999 g m o {l}^{-} 1$)

(2 xx 12.011) + (6 xx 1.008) + (1 xx 15.999) = 46.261176gmol^-1

To find the amount of ethanol:

$n \left(C {H}_{3} C {H}_{2} O H\right) = \frac{1.5 g}{46.261176 g m o {l}^{-} 1}$

$= 3.242459724759267 m o l$