8 g of O2 has the same number of molecules as:

Moles of O2​= 8​ /32 =0.25 molesNo. of molecules =No. of moles × NA​. Thus, no. of moles is directly proportional to no. of molecules.Moles of 7 gm CO= 7/28​ =0.25Moles of 14 gm CO= 14​ /28 =0.5Moles of 22 gm CO2​= 22​ /44 =0.5Moles of 11 gm of CO2 =11/44 =0.25