Question

How many moles of electrons weigh one kilogram?
A. `6.022xx10^(23)`
B. `(1)/(9.108)xx10^(31)`
C. `(6.023)/(9.108)xx10^(54)`
D. `(1)/(9.108xx6.022)xx10^(8)`

Answer 1

Correct Answer - D
Mass of one electron `=9.108xx10^(-31)kg`
`:.` 1 kg of electrons `=(1)/(9.108xx10^(-31))`
`=(10^(31))/(9.108xx6.022xx10^(23))mol`
`=(10^(31-23)"mole")/(9.108xx6.022)=(10^(8))/(9.108xx6.022)mol`