https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:kinetics/x2eef969c74e0d802:reaction-rates/v/rate-of-reaction 2021-01-30T09:10:01Z Introduction to reaction rates The rate of a chemical reaction is defined as the rate of change in concentration of a reactant or product divided by its coefficient from the balanced equation. A negative sign is used with rates of change of reactants and a positive sign with those of products, ensuring that the reaction rate is always a positive quantity. In most cases, concentration is measured in moles per liter and time in seconds, resulting in units of M/s for the reaction rate. Jay video https://cdn.kastatic.org/googleusercontent/cpSAiTKbHANKHeK8VXNbBhHsnmUEUQcPx7y9Bs_45FuGkktvAfGRpuqre4MErFJGvMJVWmKF9fwHow0hA6sF7NJ0 Introduction to reaction rates The rate of a chemical reaction is defined as the rate of change in concentration of a reactant or product divided by its coefficient from the balanced equation. A negative sign is used with rates of change of reactants and a positive sign with those of products, ensuring that the reaction rate is always a positive quantity. In most cases, concentration is measured in moles per liter and time in seconds, resulting in units of M/s for the reaction rate. https://cdn.kastatic.org/ka-youtube-converted/8wIodo1HD4Y.mp4/8wIodo1HD4Y.mp4 554 Introduction to reaction rates https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/v/collision-theory 2021-01-30T09:09:56Z Collision theory Collision theory states that molecules must collide to react. For most reactions, however, only a small fraction of collisions produce a reaction. In order for a collision to be successful, the reactant molecules must collide both with sufficient energy to overcome the activation energy barrier and in the proper orientation to form any new bonds in the products. Jay video https://cdn.kastatic.org/googleusercontent/KVNzRM6P5K59aYcHOyMgVFrq8GKsRUK3rh9_mblSqnd9RyYTNRU8NqV5R1gpqVQK05Dgl4z7KCfshabcgG_igWvr1A Collision theory Collision theory states that molecules must collide to react. For most reactions, however, only a small fraction of collisions produce a reaction. In order for a collision to be successful, the reactant molecules must collide both with sufficient energy to overcome the activation energy barrier and in the proper orientation to form any new bonds in the products. https://cdn.kastatic.org/ka-youtube-converted/1iAxhc6EflI.mp4/1iAxhc6EflI.mp4 528 Introduction to reaction rates https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/e/understand-collision-theory 2026-03-11T05:00:37.141016324Z Understand: collision theory Check your understanding of collision theory in this set of free practice questions. Allen Ruch exercise