Final answer:
Nitrogen and hydrogen react to form ammonia with a 75% yield under the conditions of the Haber process, which involves high pressure, moderate temperature, and a catalyst. The yield is not 100% due to the equilibrium nature of the reaction. Percent yield can be calculated based on the actual amount of product compared to the expected stoichiometric amount.
Step-by-step explanation:
The conditions under which nitrogen and hydrogen react to form ammonia with a 75% yield relate to the Haber process, a chemical reaction that is fundamental to the production of fertilizer from ammonia. The balanced equation for this reaction is 3 H₂(g) + N₂(g) → 2 NH₃(g). Under optimal conditions, which involve high pressure, moderate temperature, and the presence of a catalyst, a significant quantity of ammonia can be produced. However, due to the dynamic nature of the chemical equilibrium, the yield is not usually 100%.
For example, if the stoichiometry of the reaction predicts the formation of 170.0 grams of ammonia but only 6.2 moles are produced, the percent yield can be calculated. Additionally, if you start with 6.2 grams of nitrogen and obtain 6.2 grams of ammonia, the percent yield can be determined based on the initial amount of the reactant and the amount of product formed.
Knowledge of the equilibrium constant at various temperatures aids in understanding the efficiency of the reaction at different conditions, shown by values such as K₂₅°C 3.3 × 10⁹, K₁⁷⁷°C 2.6 × 10³, and K₃⁷°C 4.1. These values indicate that the reaction is highly favored at lower temperatures, but practical considerations such as reaction rate must be balanced against equilibrium considerations.