How many moles of electrons weigh one kilogram?
(Mass of electron `=9.108xx10^(-31)` kg, Avogadro's number `=6.023xx10^(23)`)

Options

A. `1/(9.108 xx 6.023) xx 10^(8)`
B. `6.023 xx 10^(23)`
C. `1/(9.108) xx 10^(31)`
D. `(6.023)/(9.108) xx 10^(54)`

Explanation

(a): Mass of one electron = `9.108 xx 10^(-31)` kg
Mass of one mole of electrons = `6.022 xx 10^(23) xx 9.108 xx 10^(-31) kg`
Now,`6.023 xx 10^(23) xx 9.108 xx 10^(-31) kg =1` mole of electrons
`therefore 1 kg = 1/(6.023 xx 10^(23) xx 9.108 xx 10^(-31)) = 1/(6.023 xx 9.108) xx 10^(8)` moles of electrons