What is an example of a limiting reagent practice problem?

In this case, which reagent is the limiting one? Assuming full combustion, how much carbon dioxide will be produced?

Do I gain five pounds?

Consider the reaction between hydrogen gas (H₂) and nitrogen gas (N₂) to produce ammonia (NH₃) according to the following balanced chemical equation:

$N_{2(g)} + 3H_{2(g)} \rightarrow 2NH_{3(g)}$

Suppose you have 5.0 moles of N₂ and 15.0 moles of H₂ available. Determine which reactant is the limiting reagent and how many moles of NH₃ can be produced.

Solution:

1. Determine the mole ratio from the balanced equation: According to the balanced equation, 1 mole of N₂ reacts with 3 moles of H₂ to produce 2 moles of NH₃.

2. Calculate the moles of NH₃ produced by each reactant:

   • For N₂: Since we have 5.0 moles of N₂, and the ratio of N₂ to NH₃ is 1:2, N₂ can produce $5.0 \times 2 = 10.0$ moles of NH₃.
   • For H₂: Since we have 15.0 moles of H₂, and the ratio of H₂ to NH₃ is 3:2, H₂ can produce $15.0 \div 3 \times 2 = 10.0$ moles of NH₃.

3. Identify the limiting reagent: Both N₂ and H₂ can produce the same amount of NH₃, so neither is in excess based on the given amounts. However, in practice, this situation indicates that both reactants are perfectly balanced to convert completely into the product without any leftover reagent.

4. Calculate the amount of product formed: Since both reactants can produce 10.0 moles of NH₃, and they are used up completely, 10.0 moles of NH₃ will be produced.

In this specific problem, neither reactant is technically limiting since they are provided in the exact stoichiometric ratio needed to react completely with each other.