Answer:
36.45 g
Explanation:
The balanced reaction given is:
2NH₃(g) + (5/2)O₂(g) → 2NO(g) + 3H₂O(l)
The molar masses of the interest compounds are:
NH₃ = 17.0 g/mol
O₂ = 32.0 g/mol
H₂O = 18.0 g/mol
First, let's find out which of the reactants will be totally consumed, the limiting, and which one is in excess.
By the reaction, the stoichiometry is:
2 moles of NH₃ -------------- 5/2 moles of O₂
Converting by mass (multiplying the molar mass by the number of moles), and supposing that all the ammonia will be consumed:
34 g of NH₃ ------------- 80 g of O₂
54.0 g ------------- x
By a simple direct three rule:
34x = 4320
x = 127 g of O₂
So, it'll be needed more oxygen than we have, so, oxygen must the limiting reactant.
The stoichiometry between oxygen and water is:
5/2 moles of O₂ -------------------- 3 moles of H₂O
Converting by mass:
80 g of O₂ ------------------------ 54 g of H₂O
54 g ------------------------ y
By a simple direct three rule:
80y = 2916
y = 36.45 g of H₂O