Final answer:
The 1:1 ratio between the ammonium ion and the acetate ion in a reaction is determined by the stoichiometry of the chemical equation and the equilibrium constant expression.
Step-by-step explanation:
The 1:1 ratio between the ammonium ion and the acetate ion in a reaction occurs because of the stoichiometry of the chemical equation and the equilibrium constant expression. In the case of the ammonium carbamate decomposition, 2 moles of ammonia gas are produced for every 1 mole of carbon dioxide, indicating a 2:1 ratio. On the other hand, the equilibrium constant expression shows that there is only 1 product, ammonia, with a coefficient of 2, while the reactants N₂ and H₂ have coefficients of 1 and 3, respectively. This results in a balanced 1:1 ratio between the ammonium ion and the acetate ion in the reaction.