Find the number of moles of water that can be formed if you have 150mol of hydrogen gas and 70mol of oxygen gas.

Reaction equation:
2H₂ + O₂ → 2H₂O

150 moles of Hydrogen requires 75 moles of Oxygen; however, 70 moles of Oxygen are present so Oxygen is the limiting reactant. We will calculate the amount of product using the amount of Oxygen.

Molar ratio of Oxygen : water:
1 : 2
Thus, moles of water = 2 x moles of oxygen
Moles of water = 2 x 70

Moles of water = 140

Qand k are only the same when the forward rate of the reaction has reached zero.