`10^(21)` molecules of `CO_(2)` were expelled from 220 mg of `CO_(2)`. How many molecules of `CO_(2)` were left?

Explanation

No. of molecules in 220 mg off `CO_(2)`
`=(220xx6.022xx10^(23))/(44000)=3.0115xx10^(21)`
As, `10^(21)` molecular of `CO_(2)` were expelled, so no. of molecules left=`(3.0115xx10^(21)-10^(21))=2.0115xx10^(21)`.