# How many oxygen molecules are present in 113.97 liters of oxygen gas at STP?

Approx. $5 \times {N}_{A} \text{ oxygen molecules where "N_A = "Avogadro's Number}$,
"Moles of dioxygen "=(113.97*L)/(22.41*L*mol^-1; here we use the molar volume to give us an answer in moles. Then we simply multiply this number by ${N}_{A}$, $\text{Avogadro's Number}$:
"Number of dioxygen molecules"=(113.97*L)/(22.41*L*mol^-1)xx6.022xx10^23*mol^-1=??;.