Question

Calculate the number of moles of electron weighing $1\mathrm{Kg}$.

Answer 1

Step 1: Analyse given data

It is given that:

Mass of electron $=9.1\mathrm{x}{10}^{-31}\mathrm{Kg}$

We need to find out moles of electrons in $1\mathrm{Kg}$

We know that one mole of electrons $=6.023\mathrm{x}{10}^{23}$ electrons

Step 2: Find number of moles of electrons

A mole is defined as the amount of a substance that contains exactly $6.02214076\mathrm{x}{10}^{23}$ ‘elementary entities’ of the given substance.

Mass of one mole of electrons $=6.023\mathrm{x}{10}^{23}\mathrm{x}9.1\mathrm{x}{10}^{-31}\mathrm{Kg}$

Number of mole of electrons that weigh one kilogram

$=\frac{1}{9.108\mathrm{x}{10}^{-31}}\mathrm{x}6.023\mathrm{x}{10}^{23}$

$=\frac{{10}^8}{9.108\times 6.023}\text{moles}$

Thus, Number of moles of electron in one kg$=\frac{{10}^8}{9.108\times 6.023}\text{moles}$