Question

How many liters of oxygen are required to react completely with 1.2 liters of hydrogen to form water?

Answer 1

Under the same conditions a volume of `0.6*L` of dioxygen is required.

Explanation:

`H_2(g) + 1/2O_2(g) rarr H_2O(l)`

Under equivalent conditions, equal volumes of gases contain equal numbers of gaseous particles. We need 1 equiv `O_2(g)` for each 2 equiv `H_2(g)`.

Answer 2

`0.6 L O_2`

Explanation:

Without the pressure and temperature we cannot calculate this value.

However, if we assume this reaction is taking place at Standard Temperature and Pressure (STP) we can use Avogadro's constant of `22.4 L` per mole.

The balanced equation for this reaction is

`2H_2 + O_2 -> 2H_2O`

Now we can use the mole ratio to convert the values.

`1.2 L H_2 * (1 mol H_2)/(22.4 L H_2) * (1 mol O_2)/(2 mol H_2) * (22.4 L O_2)/(1 mol O_2)`

`1.2 cancel(L H_2) * (1 cancel(mol H_2))/(cancel(22.4)cancel( L H_2)) * (1 cancel(mol O_2))/(2 cancel(mol H_2)) * (cancel(22.4) L O_2)/(1 cancel(mol O_2))`

`0.6 L O_2`