Question

Which of the following contains largest number of atoms ?

• A. 4 g of $H_2$
• B. 16 g of $O_2$
• C. 28 g of $N_2$
• D. 18 g of $H_{2}O$

Answer 1

Answer: (A)

4 g of $H_2$

4 g of hydrogen contains the largest number of atoms.

(A) 4 g of hydrogen (molar mass 2) corresponds to 2 moles of molecules or 4N number of atoms where N is the Avogadro's number ($6.023\times {10}^{23}$).

(B) 16 g of oxygen (molar mass 32) corresponds to 0.5 moles of molecules or N number of atoms where N is the Avogadro's number ($6.023\times {10}^{23}$).

(C) 28 g of nitrogen (molar mass 28) corresponds to 1 mole of molecules or 2N number of atoms where N is the Avogadro's number ($6.023\times {10}^{23}$).

(D) 18 g of water (molar mass 18) corresponds to 1 mole of molecules or 3N number of atoms where N is the Avogadro's number ($6.023\times {10}^{23}$).