Without doing any calculations, determine which of the following best represents the mixture after the reactants have reacted as completely as possible. Without doing any calculations, determine which of the following best represents the mixture after the reactants have reacted as completely as possible. a) 1 molNO, 0 mol H2, 4 mol NH3, 4 molH2O b) 0 molNO, 1 mol H2, 5 mol NH3, 5 molH2O c) 0 molNO, 0 mol H2, 4 mol NH3, 4 molH2O d) 3 molNO, 5 mol H2, 2 mol NH3, 2 molH2O

Since the question is incomplete, here I copy the full question:

Consider the following reaction:

2NO (g) + 5 H₂ → 2 NH₃ (g) + 2H₂O (g)

A reaction mixture contains 5 moles of NO and 10 moles of H₂. Without doing any calculations, determine which of the following best represents the mixture after the reactants have reacted as completely as possible. Explain your reasoning.

a) 1 mol NO, 0 mol H₂, 4 mol NH₃, 4 mol H₂O

b) 0 mol NO, 1 mol H₂, 5 mol NH₃, 5 mol H₂O

c) 0 mol NO, 0 mol H₂, 4 mol NH₃, 4 mol H₂O

d) 3 mol NO, 5 mol H₂, 2 mol NH₃, 2 mol H₂O

Answer:

a) 1 mol NO, 0 mol H₂, 4 mol NH₃, 4 mol H₂O.

Explanation:

The coefficients of the balanced chemical equation gives the stoichiometric mole ratios; this is, the proportion of the number of moles of each reactant that indeed react and the number of moles that can be yielded of each product.

Thus, from the balanced chemical equation, the mole ratios are:

2 mol NO (g) : 5 mol H₂ : 2 mol NH₃ (g) : 2 mol H₂O (g)

Now, the starting mixture contains 5 moles of NO and 10 moles of H₂, so:

Looking at the reactant side, focus on the number of moles of H₂: you start with 10 moles, which is the double of 5 (the stoichiometric coefficient on the chemical equation), meaning that it will be needed the double of 2 moles of NO, i. e. 4 moles. Since, there more than 4 moles of NO (5), NO is in excess and H₂ is the limiting reactant. Then, when the 10 moles of H₂ have reacted, 4 moles of NO will have reacted and 1 mol of NO will remain (in excess).

Summarizing: after the reaction, there will be 1 mol NO and 0 mol H₂.

Now let's look at the product side: the number of moles produced of each substance will be the double of what the stoichiometric coefficientes indicate, i. e. 4 mol NH₃ and 4 mol H₂O.

At the end, you have determined, without calculations, that the mixture after the reactants have reacted as completely as possible, is represented by the first option:

a. 1 mol NO, 0 mol H₂, 4 mol NH₃, 4 mol H₂O.