Question

How many moles are in $508$ grams of ethanol?

Answer 1

Hint:To determine the answer to this question we should know the mole formula. First, we have to determine the molar mass of ethanol. For this we should know the molecular formula of ethanol if not given. Then we will calculate the moles of ethanol in the given gram. For this, we will use the mole formula.

Formula used: ${\text{mole}}\,\,{\text{ =}}\,\dfrac{{{\text{mass}}}}{{{\text{molar}}\,\,{\text{mass}}}}$

Complete step-by-step answer:The given molecular formula of ethanol is ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{6}}}{\text{O}}$ .
The atomic mass of carbon is $12.01$ g/mol.
The atomic mass of hydrogen is $1.00$ g/mol.
The atomic mass of oxygen is $16.00$ g/mol.
So, the molar mass of ethanol is,
$\left( {12.01 \times \,2} \right)\, + \,\left( {1.00\,\, \times \,6} \right) + \left( {16.00\,\, \times \,1} \right)$
 $46.02$g/mol
We will use the mole formula to determine the number of moles of ethanol as follows:
${\text{mole}}\,{\text{ = }}\,\dfrac{{{\text{mass}}}}{{{\text{molar}}\,{\text{mass}}}}$
The molar mass of ethanol is $46.02$ g/mol.
On substituting $508$ grams for the mass of ethanol and $46.02$for molar mass of ethanol,
${\text{mole}}\,{\text{ = }}\,\dfrac{{508}}{{46.02}}$
$\therefore {\text{mole}}\,{\text{ = }}\,11.04$
So, the moles of the ethanol is $11.04$ mol.

Therefore, $11.04$moles are in $508$ grams of ethanol.

Note:The number of atoms present in $12\,{\text{g}}$ of carbon-12 is known as one mole. The mass is taken into grams. The unit of moles is mol. So, the unit of molar mass is g/mol. The atomic mass is the sum of the number of protons and neutrons. The mass of one mole of a molecule is known as molar mass. The molar mass of a molecule is the sum of the atomic mass of all constituting atoms. Mol is the unit of substance. One mole of a substance contains $6.022 \times {10^{23}}$ particles such as atoms, molecules or ions of that substance. The number $6.022 \times {10^{23}}$ is known as Avogadro number.