DAILY QUESTION November 4, List 5 factors that may affect the rate of a chemical reaction.

Agenda11/4/08 Daily Question Ch 6 Section 4 Notes Assignments:1. Studyguide due 11/6 2. Ch 6 Sects 3 and 4 Wksht due 11/6

Factors affecting reaction rates Temperature: –Heating speeds up chemical reactions –Cooling slows down chemical reactions The kinetic theory states that particles move faster at higher temperatures; thus faster moving particles collide more often and more chances for the particles to react.

Factors affecting reaction rates Surface Area: –Large surface area speeds up reaction A large surface area allows more particles to come in contact with the other reactants

Factors affecting reaction rates Concentration: –Concentrated solutions react faster The more concentrated solution has a higher number of particles, which means a higher chance for particle collisions

Factors affecting reaction rates Pressure: –Higher pressures cause a faster reaction Gases react faster at higher pressures, the particles have less space so they have more collisions.

Factors affecting reaction rates Nature of reactants: –Massive, bulky molecules react slower –Small molecules react faster The size and shape of reactant molecules affects the rate of reaction.

Catalysts Not a reactant or product They speed up or slow down reactions –Inhibitors – slow down reactions Can be reused Name of catalyst can be written over the reaction arrow of a chemical equation Work in many different ways

Enzymes Protein that are catalysts for chemical reactions in living things Very specific –Each enzyme controls one reaction or set of similar reactions Fragile Decompose if too warm or too cold Examples: Lipase, Protease (Table 1 pg 207)

Substrate The reactant in reactions catalyzed by enzymes