# How many liters of nitrogen monoxide will be obtained from 2.50 liters of oxygen if the temperature and pressure are constant?

Quite probably $5.0 \cdot L$.....
$\frac{1}{2} {N}_{2} \left(g\right) + \frac{1}{2} {O}_{2} \left(g\right) \rightarrow N O \left(g\right)$
Here, $2.5 \cdot L$ of dioxygen gas reacts with $2.5 \cdot L$ of dinitrogen gas to give $5.0 \cdot L$ of $N O$ gas. As always, the answer is defined by the stoichiometry of the chemical equation.