If `10^(21)` molecules are removed from 200 mg of `CO_(2)`, the number of moles of `CO_(2)` left will be ?

Options

A. `2.88 xx 10^(-3)`
B. `1.66xx 10^(-3)`
C. `4.54 xx 10^(-3)`
D. `1.66xx 10^(-2)`

Answer

A

Explanation

`6xx10^(23)" molecules of " CO_2 -= 1 " mole"`
`1xx10^(21)` molecules of `CO_2-=(10^(21)xx1)/(6xx10^(23))= 1.66xx10^(-3)`
44 g of `CO_2-= 1" mole"`
`200xx10^(-3)g " of "CO_2 -= (200xx10^(-3))/(44) = 4.54xx10^(-3)` mole
Moles of `CO_2` left `=4.54 xx10^(-3)-1.66xx10^(-3)`
`=2.88xx10^(-3)`