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 Rates of chemical reactions https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/e/understand-collision-theory 2026-04-29T07:20:45.495372596Z Understand: Collision theory Check your understanding of collision theory in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/v/factors-affecting-reaction-rates 2022-10-05T02:43:18.611402953Z Factors affecting reaction rates The rate of a chemical reaction is influenced by many different factors, including reactant concentration, surface area, temperature, and catalysts. In general, increasing the concentration of a reactant in solution, increasing the surface area of a solid reactant, and increasing the temperature of the reaction system will all increase the rate of a reaction. A reaction can also be sped up by adding a catalyst to the reaction mixture. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/b2fb2453-05c7-482e-98ee-0bb9abf02353_1280_720_base.png Factors affecting reaction rates The rate of a chemical reaction is influenced by many different factors, including reactant concentration, surface area, temperature, and catalysts. In general, increasing the concentration of a reactant in solution, increasing the surface area of a solid reactant, and increasing the temperature of the reaction system will all increase the rate of a reaction. A reaction can also be sped up by adding a catalyst to the reaction mixture. https://cdn.kastatic.org/ka-youtube-converted/CoNHV7786Hg.mp4/CoNHV7786Hg.mp4 329 Rates of chemical reactions https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/e/understand-factors-affecting-reaction-rates 2026-06-25T09:10:34.765500454Z Understand: Factors affecting reaction rates Check your understanding of factors affecting reaction rates in this set of free, standards-aligned practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:reaction-rates/e/apply-factors-affecting-reaction-rates 2026-06-30T16:30:41.535282189Z Apply: Factors affecting reaction rates Apply your understanding of factors affecting reaction rates in this set of free, standards-aligned practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:reaction-rates-and-equilibrium/x2613d8165d88df5e:activity-why-does-food-in-a-refrigerator-stay-fresh-for-longer/a/activity-why-does-food-in-a-refrigerator-stay-fresh-for-longer 2026-01-14T23:20:41.344464701Z Activity: Why does food in a refrigerator stay fresh for longer? Make science come alive in your classroom with this free hands-on activity aligned to high school standards. article