From 200mg of `CO_2, 10^21` molecules are removed. How many moles of `CO_2` are left?

Explanation

Number of `CO_2` molecules in 200g = `(6.22xx10^23/44) xx 0.2 = 2.74 xx 10^21`
Number of `CO_2` molecules left = `(2.74-1)10^21 = 1.74xx 10^21`
Number of moles of `Co_2` left = `(1.74xx10^21)/(6.222xx10^23) = 2.89 xx 10^23`