Question

How do you calculate the number of moles?

Answer 1

Hint Mole of a substance describes us about the quantity of that very substance and if we know the mass and the molar mass of that very substance, then by using them we can easily calculate the number of moles of the substance.

Complete answer:
First of all, let’s discuss the mole. Mole is that which tells us about the amount or the quantity of the substance. It can be in terms of either atoms , molecules , particles or grams, liters etc.
Now considering the statement as;
To calculate the number of moles of any substance, we should first know about the given mass and the molar mass of that very substance i.e., the atom or molecule and then, we can easily calculate the moles of that very atom or molecule by using the formula as;
$mole=\dfrac{given\text{ }mass}{Molar\text{ }mass}$
Example:-Suppose the given mass of the sodium atom in the statement is 12.
And we know that the molar mass of sodium atoms is 23.
Then, the number of moles of sodium atom comes out to;
Applying the mole formula, we get;
$mole=\dfrac{given\text{ }mass}{Molar\text{ }mass}=\dfrac{12}{23}=1.52\text{ moles}$
So, thus the number of moles of sodium atom according to the given statement comes out to be $1.52\text{ moles}$.
Similarly, by using this formula, we can easily calculate the number of moles for any substance i.e., atom or molecules.

Note: According to the Avogadro’s law, one mole of the substance whether atoms or molecules or gas, at the standard conditions of temperature and pressure i.e., 1 atmosphere pressure and $273$ kelvin temperature contains Avogadro number of particles ($6.023\times {{10}^{23}}$) and occupies $22.4$ liters of volume.