rates of reaction

• reactions happen at varying rates. for example, a firework exploding is a fast reaction whereas a piece of iron rusting would take place over a long period of time.
• the rate of a chemical reaction tells us how quickly a product is formed or how quickly a reactant is used up.
• for a chemical reaction to occur, the reactant particles must collide with enough energy. those collisions that produce a chemical reaction are successful.
• mean rate of reaction = quantity of reactant used / time taken
• mean rate of reaction = quantity of product produced / time taken
• the changing mass of a reaction mixture can be measured during a reaction. this method is particularly useful when gases are given off as gas escaped during the reaction and the mass of the reaction mixture decreases.
• units = g/s or g/min