FACTORS THAT AFFECT THE RATE OF A REACTION

molecules are always moving i.e. they have kinetic energy July 2, Kinetic Molecular Theory State of Matter Simulation

the rate of reaction is affected by the number of collisions of reactant molecules How do you make a reaction go faster? 1. increase the number of collisions 2. increase the number of collisions that are effective July 2, Collision Model

The are 4 main factors that affect the rate of a reaction: 1.Temperature: if temperature of reactants ↑ average speed of the molecules ↑ molecules collide more often & more effectively reaction rate ↑ July 2, Factors that Affect the Rate of a Reaction

2.Concentration/Pressure: if concentration of a reactant ↑ more molecules are packed into the same space, therefore molecules collide more often reaction rate ↑ July 2, Factors that Affect the Rate of a Reaction

3.Surface Area: area of a sample of matter that is visible & able to react with other matter surface area can be increased by decreasing the sizes of the pieces of the reactants increase in surface area, increases rate of reaction July 2, Factors that Affect the Rate of a Reaction

3.Surface Area: July 2, Factors that Affect the Rate of a Reaction

4.Catalyst: a substance that increases the rate of a chemical reaction, but is not used up in the reaction how? allow bonds in the reactants to break more readily and new bonds to form more easily catalysts for biological reactions are called enzymes July 2, Factors that Affect the Rate of a Reaction

Exothermic & Endothermic Reactions Exothermic: reaction releases energy (heat) to the surrounding environment container feels warm/hot to touch Endothermic: reaction absorbs energy (heat) from the surrounding environment container feels cool/cold to touch July 2, Endothermic Video

Homework 1.How could you use your knowledge of factors that affect the rate of reaction to cook a steak as quickly as possible? 2. What effect on the rate of reaction of a metal with 20 mL of dilute acid at room temperature would you expect if… a) the acid was cooled to 10 °C? b) 2 mL of concentrated acid was added? c) the metal was ground into powder before addition to the acid? 3.When fruit is cut into pieces, it spoils quickly. Explain. July 2,