The factors influencing the reaction rate (1). How often do the reactant molecules meet? Concentration! (2). How often do the encountered reactant molecules lead to a reaction? High enough kinetic energy to break the chemical bonds in the reactants, temperature (3 ). Sometimes, electromagnetic fields, such as sunlight, may also lead to reactions Before collision Collision After collision (a)Effective collision 9a9. Before collision Collision After collision (b)Ineffective collision Fig 9.7 during a reaction, reactant molecules collide with each otherThe factors influencing the reaction rate: (1). How often do the reactant molecules meet? Concentration! (2). How often do the encountered reactant molecules lead to a reaction? High enough kinetic energy to break the chemical bonds in the reactants, temperature! (3). Sometimes, electromagnetic fields, such as sunlight, may also lead to reactions. Fig 9.7 during a reaction, reactant molecules collide with each other