When 3 Moles of Nitrogen React with 5 Moles of Hydrogen: Stoichiometry and Limiting Reactant Analysis

Understanding the concept of limiting reactants in a chemical reaction is crucial for both academic and industrial applications. This article will walk you through the process of identifying which reactant is present in a smaller amount when dealing with the reaction between nitrogen and hydrogen to form ammonia. We will start by balancing the chemical equation, then analyze the stoichiometry to determine the limiting reactant.

Balancing the Chemical Equation

The reaction between nitrogen (N2) and hydrogen (H2) to form ammonia (NH3) can be described by the following balanced equation:

N2 3H2 → 2NH3

Stoichiometry and Limiting Reactant Analysis

To determine which reactant is present in a smaller amount, we need to analyze the stoichiometric coefficients of the balanced equation and compare them with the actual amounts of reactants available.

Balanced Equation Analysis:
From the balanced equation, we see that 1 mole of nitrogen (N2) reacts with 3 moles of hydrogen (H2) to produce 2 moles of ammonia (NH3). Given Reactant Amounts:
Nitrogen (N2): 3 moles
Hydrogen (H2): 5 moles Determine Required Moles of Hydrogen:
According to the stoichiometry, to fully react with 3 moles of nitrogen, we would need 9 moles of hydrogen (since 1 mole N2 requires 3 moles H2). Compare Actual and Required Amounts:
Since we only have 5 moles of hydrogen available, it is clear that hydrogen is the limiting reactant. Conclusion:
H2 is the reactant present in a smaller amount and will be completely used up before the nitrogen, causing the reaction to cease.

Therefore, hydrogen (H2) is the limiting reactant in this scenario.

Steps for Identifying Limiting Reactant

To systematically identify the limiting reactant in any chemical reaction, follow these steps:

Write and balance the chemical equation. Divide the number of moles of each reactant by its corresponding stoichiometric coefficient. The lower ratio indicates the limiting reactant.

Example Analysis

In your case, since the reaction between nitrogen and hydrogen follows a 1:3 mole ratio, hydrogen (H2) will be the limiting reactant. To verify this:

1 mole of N2 reacts with 3 moles of H2 to form 2 moles of NH3. Therefore, for 3 moles of N2, we need 9 moles of H2. With only 5 moles of H2 available, hydrogen is the limiting reactant.

Conclusion

The limiting reactant concept is essential for optimizing chemical reactions and ensuring efficient use of resources. By understanding stoichiometry and identifying the limiting reactant, chemists can avoid waste and improve the efficiency of their processes.

For more detailed guidance and additional practice problems on stoichiometry and limiting reactants, refer to textbooks or online resources on chemistry.