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

Options

A. `2.88xx10^(-3)`
B. `1.66xx10^(-3)`
C. `4.54xx10^(-3)`
D. `1.66xx10^(-2)`

Answer

A

Explanation

200 mg of `CO_(2)=0.200g=(0.2)/(44)mol`
`=(0.2)/(44)xx6.023xx10^(23)` molecules
After removing `10^(21)` molecules, molecules left
`=(2.738-1)10^(21)=1.738xx10^(21)` molecules
`=(1.738xx10^(21))/(6.022xx10^(23))mol=2.88xx10^(-3)mol.`