Which of the following has the most number of moles?

(Atomic mass- C=12 u, O=16 u, H=1 u, N=14 u)

Number of moles=$\frac{\mathrm{Mass} \mathrm{in} \mathrm{g}}{\mathrm{Molar} \mathrm{mass}}$

$$\begin{gathered} \mathrm{Number} \mathrm{of} \mathrm{moles} \mathrm{in} 22 \mathrm{g} {\mathrm{CO}}_2 \\ =\frac{22}{44}=\frac{1}{2} \mathrm{moles} \end{gathered}$$

$\mathrm{Number} \mathrm{of} \mathrm{moles} \mathrm{in} 1 \mathrm{g} {\mathrm{CH}}_4=\frac{1}{16}$

$\mathrm{Number} \mathrm{of} \mathrm{moles} \mathrm{in} 0.5 \mathrm{g} {\mathrm{H}}_2 =\frac{1}{8} \mathrm{moles}$

$$\begin{gathered} \mathrm{Number} \mathrm{of} \mathrm{moles} \mathrm{in} 1 \mathrm{g} {\mathrm{N}}_2 \\ =\frac{1}{28} \mathrm{moles} \end{gathered}$$

Hence, 22g of CO₂ will have the most moles.