Final answer:
To find the equilibrium concentration of each substance in a mixture at 25°C involving a nickel catalyst, an ICE table and the equilibrium constant expression are used, considering the initial concentrations and the large value of K (9.6 × 10¹⁸) indicating nearly complete reaction.
Step-by-step explanation:
The student's question relates to the equilibrium concentration of substances involved in a chemical reaction where solid nickel acts as a catalyst. Given that the balanced chemical equation is known, along with the equilibrium constant (K) and initial concentrations of reactants, the goal is to find the equilibrium concentrations of each substance in the mixture at 25°C.
First, we need to establish the balanced chemical equation for the reaction. Since we are dealing with nickel catalyst, it's likely a hydrogenation reaction occurring in this scenario. The general approach involves determining the changes in concentration (Δ) from the initial state to the equilibrium state using an ICE (Initial, Change, Equilibrium) table. This method allows us to apply the equilibrium constant expression to solve for unknown equilibrium concentrations.
Without the exact equation, let's consider a hypothetical reaction: C₂H₄(g) + H₂(g) → C₂H₆(g). If we start with 0.200 M H₂ and 0.155 M C₂H₄, and knowing K is significantly large (9.6 × 10¹⁸), the reaction will proceed nearly to completion. Thus, the equilibrium concentrations of reactants will be close to zero, and the concentration of C₂H₆ will be approximately the sum of the initial concentrations of H₂ and C₂H₄, assuming complete conversion. Calculations would need to be adjusted based on the actual balanced equation provided in the assignment.