Question

Determine the number of moles present in0.55mg of electrons

Answer 1

Mass of an electron is 9.1*10^-31 kg

=9.1*10^-31*10^6 mg

=9.1*10^-25 mg

So, 9.1*10^-25 mg contains 1 electron

or, 1 mg contains 1/ (9.1*10^-25) electrons

So, 0.55 mg contains 1/(9.1*10^-25)*0.55 electrons

=6.043956044*10^23 electrons

Now simply apply Avogadro's law,

6.023*10^23 electrons make 1 mole

or 6.043956044*10^23 electrons make 1.0035 moles ~~1 mole

So it’s 1 mole……