1.0 g of H_2 has same number of molecules as in:

Number of moles of $\mathrm{H}_2=\frac{1}{2}=0.5$ Number of molecules of $\mathrm{H}_2=0.5 \mathrm{~N}_{\mathrm{A}}$. (1) Number of moles of $\mathrm{N}_2=\frac{14}{28}=0.5$ Number of molecules of $\mathrm{N}_2=0.5 \mathrm{~N}_{\mathrm{A}}$ (2) Number of moles of $\mathrm{H}_2 \mathrm{O}=\frac{18}{18}=1$ Number of molecules of $\mathrm{H}_2 \mathrm{O}=1 \times \mathrm{N}_{\mathrm{A}}=\mathrm{N}_{\mathrm{A}}$ (3) Number of moles of $\mathrm{CO}=\frac{16}{28}=\frac{4}{7}$ Number of molecules of $\mathrm{CO}=\frac{4}{7} \mathrm{~N}_{\mathrm{A}}$ (4) Number of moles of $\mathrm{N}_2=\frac{28}{28}=1$ Number of molecules of $\mathrm{N}_2=1 \times \mathrm{N}_{\mathrm{A}}=\mathrm{N}_{\mathrm{A}}$