The number of moles left = 0.0067 moles
Further explanation
Given
0.28 g CO
2 x 10²¹ molecules removed
Required
Number of moles left
Solution
Initial mol of CO(MW=28 g/mol) :
mol = 0.28 : 28
mol = 0.01
The number of molecules in 0.01 mol :
= 0.01 x 6.02 x 10²³
= 6.02 x 10²¹
2 x 10²¹ molecules removed, so molecules left :
= 6.02 x 10²¹ - 2 x 10²¹
= 4.02 x 10²¹
moles of 4.02 x 10²¹ :
= 4.02 x 10²¹ : 6.02 x 10²³
= 0.0067 moles
