Arrange the following samples of oxygen gas ( O₂ ) in increasing order of the number of molecules present in them: (I) 1.6 g of O₂ (II) 22.4 L of O₂ at STP (III) 0.08 mol of O₂ (IV) 32 u of O₂

Step-by-step solution

Calculate the number of moles or molecules for each sample: (I) 1.6 g of O₂ : Moles = 1.6 32 = 0.05 mol . Number of molecules = 0.05 N_A . (II) 22.4 L of O₂ at STP: Moles = 22.4 22.4 = 1 mol . Number of molecules = N_A . (III) 0.08 mol of O₂ : Number of molecules = 0.08 N_A . (IV) 32 u of O₂ : Since the molecular mass of one O₂ molecule is 32 u , this represents exactly 1 molecule. Comparing the number of molecules: 1 Thus, the increasing order is (IV) Answer: (IV) < (I) < (III) < (II)