Mass of one atom of X is `6.66xx10^(-23)g`. Hence number of mole of atom X in 40kg is

Options

A. `10 ^(3)` mol
B. `10 ^(-3)` mol
C. `( 40 xx 10 ^(3))/(6.66 xx 10 ^(-23)) mol`
D. `(40 xx 10 ^(3))/( 6. 022 xx 10 ^(23)) mol`

Answer

A

Explanation

Mass of one atom `= 6.66 xx 10 ^(23) g `
`therefore` Atomic mass `= 6.66 xx 10 ^(-23) xx 6. 02 xx 10 ^(23) = 40 g mol ^(-1)`
`therefore ` No of moles in `40 kg = ( 40000 g)/(40 g mol ^(-1)) = 1000 mol`