Chapter 16 rates of reaction Flashcards
rate of reaction
defined as the change in concentration per unit time of any product / reactant
instantaneous rate of reaction
the rate of reaction at any one particular point in time
factors affecting the rates of reaction (5)
nature of reactants(covalent/ionic) , particle size (SA), concentration, temperature , catalysts
catalyst
a substance that alters the rate of a chemical reaction but is not used up itself in the reaction
enzyme
substance produced by a living cell and acts as a biological catalyst
homogeneous catalyst
catalysis in which both the reactants and the catalyst are in the same phase
heterogeneous catalyst
catalysis in which the reactants and catalyst are in different phases
autocatalysis
catalysis in which one of the products acts as a catalyst for the reaction
evidence for the intermediate formation theory
(using potassium sodium tartrate + hydrogen peroxide)
color change from pink to green and then back to pink the green indicating the substance is an intermediate
the surface absorption theory + stages
(consider 2H2 + O2 > 2H2O [in the presence of platinum] ) Absorption stage = platinum forms temporary bonds with the H and the O , Surface reaction stage = particles collide, desorption stage = products leave the surface of the catalyst
catalyst poisson + example
substance that stops the catalyst from working by blocking the surface eg: lead , sulfur
catalytic converter
a device in the exhaust system of a motor vehicle which contains catalysts to convert pollutants into less harmful substances. (contains platinum, palladium and rhodium)
important eq. that occurs in a catalytic converter
2CO + 2NO = 2CO2 +N2
activation energy
min. energy required which colliding particles must have for effective collisions to occur
opposite of catalyst
inhibitor
