Question

How many moles of glucose, ${{C}_{6}}{{H}_{12}}{{O}_{6}}$ are present in $300g$ of glucose?

Answer 1

The question is based on the concept of number of moles and Molar Mass of a compound. One mole of any compound contains mass equal to its molar mass. In this question we are asked to find out the number of moles in $300g$ of glucose.
We know that number of moles in any compound is given by the formula mentioned below,
$\text{Number of moles}$ = $\dfrac{given\,mass}{Molar\,mass}$
We will use the above formula to calculate the number of moles in $300g$ of glucose molecules.

Complete step-by-step answer:
Firstly, let us calculate the molar mass of the glucose. To find the molar mass we need to add the masses of individual elements which constitute one glucose molecule.
Now, we know that
Molar mass of Carbon $C=12gmo{{l}^{-1}}$
Molar mass of Hydrogen $H=1gmo{{l}^{-1}}$
Molar mass of oxygen $O=16gmo{{l}^{-1}}$
Therefore, Molar Mass of glucose $({{C}_{6}}{{H}_{12}}{{O}_{6}})$ can be calculated as shown below
$\Rightarrow$ $6\times 12+12\times 1+6\times 16$
$\Rightarrow 72+12+96 \\\ \Rightarrow 180gmo{{l}^{-1}} \\\$
Given mass of glucose = $300g$
Now, we can calculate the number of moles in given mass of glucose, using the below formula,
Using the Formula $number\,of\,moles=\,\,\dfrac{given\,mass}{molar\,mass}$ we get
$number\,of\,moles\,=\,\,\dfrac{300}{180}$ = $1.7$ moles or $2$ moles (approx.)
Hence the number of moles present in $300$ g of glucose is $1.7$ moles or $2$ moles approximately.

Note: Always remember that the mole of a substance always contains the same number of entities, no matter what the substances may be. It should be noted that one mole of any substance contains $6.02\times {{10}^{23}}$ atoms/ions/molecules etc. This number is termed as the Avogadro number which is denoted by $\left( {{N}_{A}} \right)$ in honor of Amedeo Avogadro.