By Vallarie Burge, Rowan Neall

Faculty Mentor: Leanna Giancarlo

Abstract

The synthesis of ammonia (NH3) is an important step in the production of fertilizers that increase the level of nitrogen in soil, bettering plant structure and metabolism. The kinetics of NH3 synthesis was examined and analyzed utilizing transition state theory (TST) in order to understand why the reaction is slow despite being spontaneous. A reaction of dinitrogen (N2) and dihydrogen (H2) was calculated thermodynamically through ChemCompute for each step of the reaction along with each transition state ten steps. The total values for enthalpy, entropy, and Gibbs free energy were recorded for each step-in order to determine the rate constants of the reaction. The production of NH3 from N2 and H2 is a reversible reaction. Utilizing the Arrhenius equation and TST, the rate constants were calculated and plotted on an energy diagram for the total reaction. Four transition states were observed, and eight rate constants were calculated. The energy diagram demonstrated an overall loss in energy confirming an exothermic reaction. The results were consistent with the Gibbs free energy and enthalpy yielding negative values. In accordance with Le Chatelier’s Principle, a lower temperature reaction will yield more NH3.The lower temperature leads to the slower reaction thus in order to realistically produce NH3 a temperature compromise must be made. ChemCompute demonstrated the efficiency and feasibility of NH3 production and allowed for an understanding of its kinetics before undergoing the experiment in real time. Further an understanding of the exothermic reaction and the conditions of the reaction were determined through the rate constants without sacrificing the integrity of the products.