Introduction

You should be aware of these numbers to calculate the number of electron moles in a kilogram.

Mass of an electron = 9.108\times 10^{-31}

Kg

And, the number of electrons in 1 mole = 6.023\times 10^{23}

electrons.

Calculate the mass of one mole of electrons first, and then use the unitary method to determine how many moles of electrons are present in one kilogram.

Calculation

One mole of a substance contains 6.023\times 10^{23} electrons (Avogadro number, N_{A} )with an electron having a mass of 9.108\times 10^{-31} .

Therefore, the mass of one mole of electrons = mass of 1 electron X number of electrons in 1 mole

= mass of 1 mole of electrons = (9.108\times 10^{-31}) \times (6.023\times 10^{23})

= kg

So, the number of electrons present in one kilogram is -

Given total mass = 1 kg

1 mole of electrons contain = (9.108\times 10^{-31}) \times (6.023\times 10^{23})

kg

1 kg contains = \frac{1}{(9.108\times 10^{-31}) \times (6.023\times 10^{23})}

moles of electrons

Or, 1 kg will contain = \frac{1}{9.108\times6.023}\times 10^{8}

moles of electrons.

Conclusion

Thus, \frac{1}{9.108\times6.023}\times 10^{8} moles of electrons will weigh one kilogram.