Answer:
5.52 g
Explanation:
First we convert the given masses of both reactants into moles, using their respective molar masses:
Now we calculate with how many NH₃ moles would 0.056 O₂ moles react, using the stoichiometric coefficients:
As there more NH₃ moles than required, NH₃ is the excess reactant.
Then we calculate how many NH₃ moles remained without reacting:
Finally we convert NH₃ moles into grams: