Steady-State Approximation: A → I → P Kinetics (2D)

A consecutive reaction A → I → P is one of the workhorses of physical chemistry, and the steady-state approximation (SSA) is the trick that turns its coupled differential equations into a usable rate law. This 2D simulator runs the reaction three ways at once: as a swarm of individual molecules bouncing in a flat vessel you can pan and zoom, each one flipping species according to a real first-order probability every frame; as the exact closed-form solution plotted against the textbook SSA prediction for the intermediate over time; and as a phase-space trajectory of [I] against [A] that shows the trajectory collapsing onto the SSA's straight-line "slow manifold" exactly when the theory says it should — and pulling away from it when it doesn't. Drag k₁ and k₂ apart or together and watch all three views respond together.