Consider the reaction represented by the unbalanced equation: NH3 + O2 → NO + H2O. For every 259 molecules of ammonia that reacts, _____ molecules of oxygen are required.

Answer 1

In stoichiometry (balanced equations), moles and molecules are pretty much interchangeable.

So, first you MUST balance the equation:

4NH₃ + 5O₂ ==> 4NO + 6H₂O ... balanced equation

Now simply use the stoichiometry of the balanced equation along with dimensional analysis:

259 molecules NH₃ x 5 molecules O₂ / 4 molecules NH₃ = 324 molecules O₂ required