2. at stp, how many liters of oxygen are required to react completely with 3.6 liters
of hydrogen to form water?
2h2(g) + o2(g)
2h20(g)

1.8 L.

Explanation:

2H₂(g) + O₂(g) → 2H₂O(g),

It is clear that 2.0 moles of H₂ react with 1.0 mole of O₂ to produce 2.0 moles of H₂O.

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication:

1.0 mol of H₂ represents → 22.4 L.

??? mol of H₂ represents → 3.6 L.

∴ 3.6 L of H₂ represents = (1.0 mol)(3.6 L)/(22.4 L) = 0.1607 mol.

Using cross multiplication:

2.0 mol of H₂ react completely with → 1.0 mol of O₂, from stichiometry.

0.1607 mol of H₂ react completely with → ??? mol of O₂.

∴ The no. of moles of O₂ = (1.0 mol)(0.1607 mol)/(2.0 mol) = 0.08036 mol.

1.0 mol of O₂ represents → 22.4 L, at STP.

0.08036 mol of O₂ represents → ??? L.

∴ The no. of liters of O₂ will be produced = (0.08036 mol)(22.4 L)/(1.0 mol) = 1.8 L.

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >