# Water can be formed according to the equation: 2H_2 + O_2 -> 2H_20. If 8.0 L of hydrogen is reacted at STP, exactly how many liters of oxygen at STP would be need to allow complete reaction?

May 28, 2016

$4.0 \cdot L$ of dioxygen gas are required.
$2 {H}_{2} \left(g\right) + {O}_{2} \left(g\right) \rightarrow 2 {H}_{2} O \left(l\right)$
Avogadro's gas law holds that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules (i.e. Vpropn). It follows that different volumes of gases under equivalent conditions contain numbers of molecules proportional to their respective volumes.
Given $8.0 \cdot L$ dihydrogen gas, $4.0 \cdot L$ dioxygen gas are required; i.e. the respective gas volumes follow the stoichiometry of the equation.