Water can be formed according to the equation: 2h2 (g) + o2 (g) → 2h2o (g) if 8.0 l of hydrogen is reacted at stp, exactly how many liters of oxygen at stp would be needed to allow complete reaction?

3.99  liters of oxygen at STP would be needed to allow complete reaction.

Explanation:

At STP, 1 mol of gas occupies = 22.4 L

Then 1 Liter of volume will be occupied by:

The 8 Liter of volume will be occupied by:

Moles of hydrogen gas = 0.3571 mol

According to reaction, 2 moles of hydrogen gas reacts with 1 mol of oxygen gas.

Then 0.3571 moles of hydrogen gas will react with:

of oxygen

Moles of oxygen required to react completely = 0.1785 moles

At STP, 1 mol of gas occupies = 22.4 L

Then 0.1785 moles of oxygen will occupy:

3.99  liters of oxygen at STP would be needed to allow complete reaction.

i do not get it   at all