Which of the following contain the same number of atoms ? (Given : Molar mass in g mol^ -1 of H, He, O and S are 1, 4, 16 and 32 respectively) A. 2 g of O_2 gas B. 4 g of SO_2 gas C. 1400 mL of O_2 at STP D. 0.05 L of He at STP E. 0.0625 mol of H_2 gas Choose the correct answer from the options given below :
D. A, C and E only
Number of atoms is calculated as the product of the number of moles, atomicity, and Avogadro's number (N_A). For A: Moles of O_2 = 2 32 = 1 16 mol. Atomicity of O_2 is 2. Number of atoms = 1 16 2 N_A = 1 8 N_A For B: Moles of SO_2 = 4 64 = 1 16 mol. Atomicity of SO_2 is 3. Number of atoms = 1 16 3 N_A = 3 16 N_A For C: Moles of O_2 at STP = 1400 22400 = 1 16 mol. Atomicity of O_2 is 2. Number of atoms = 1 16 2 N_A = 1 8 N_A For D: Moles of He at STP = 0.05 22.4 = 1 448 mol. Atomicity of He is 1. Number of atoms = 1 448 1 N_A = 1 448 N_A For E: Moles of H_2 = 0.0625 = 1 16 mol. Atomicity of H_2 is 2. Number of atoms = 1 16 2 N_A = 1 8 N_A Comparing the number of atoms, A, C, and E contain the same number of atoms. Answer: A, C and E only
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