# How many liters of oxygen are required to react completely with 2.4 liters of hydrogen to form water? 2H_2(g) + O_2(g) -> 2H_2O(g)?

Apr 30, 2017

#### Answer:

Why $1.2 \cdot L$ precisely..........

#### Explanation:

Recall old Avogadro's hypothesis...........

$\text{Equal volumes of gases contain AN EQUAL NUMBER of PARTICLES}$

And thus if there are $2.4 \cdot L$ of dihydrogen, stoichiometric equivalence requires $1.2 \cdot L$ of dioxygen. How many litres of water gas result?

Apr 30, 2017

#### Answer:

$1.2 L$

#### Explanation:

Know that one mole of any gas at STP takes up 22.4 liters. So 2.4 L of hydrogen is $0.107142857 m o l s {H}_{2}$.

Since ${H}_{2}$ reacts with ${O}_{2}$ in a 2:1 ratio, to completely react the two you will need half as much oxygen as hydrogen.

$\text{mols } {O}_{2} = \frac{0.107142857 m o l s {H}_{2}}{2}$

$\text{mols } {O}_{2} = 0.053571429 m o l s$

To find liters of oxygen, just multiply the moles above by 22.4 liters.

$\text{liters } {O}_{2} = 0.053571429 m o l s \cdot 22.4 \frac{L}{m o l s}$

$\text{liters } {O}_{2} = 1.2 L$