How many moles of electrons weigh one kilogram?

Options

A. `6.02 xx 10 ^(23)`
B. `(1)/(9.108) xx 10 ^(31)`
C. `(6.02)/(9.108) xx 10 ^(54)`
D. `(1)/(9. 108 xx 6. 02) xx 10 ^(8)`

Answer

D

Explanation

Mass of an electron `= 9.108 xx 10 ^(-31) kg `
Mass of 1 mol electron `= 6. 02 xx 10 ^(23) mol ^(-1) xx 9.108 xx 10^(-31) kg`
`therefore 1kg` of electron will contain `= (1 kg)/( 6. 02 xx 10 ^(23) mol ^(-1) xx 9.108 xx 10 ^(-31) kg) = (1)/(6. 02 xx 9. 108) xx 10 ^(8) mol`