Chunking the material: T16 Arrhenius Theory Arrhenius Equation k = A exp(- E a / RT ) *Factors that affect reaction rates: nature of reactants , T , concentration , P or V (gases), surface area (solids), catalysts *Calculate activation energy based on k vs T data *Use Arrhenius equation to perform calculations for k as a function of changing temperature or changing activation energy Reaction coordinate plots *Recognize activation energy , intermediates , transition states , and reaction enthalpy on reaction coordinate plots *Know that catalysts change the rate of a chemical reaction by providing an alternative rxn pathway with lower activation energy (e.g. enzymes); homogeneous vs heterogeneous catalysts
Factors that influence Reaction Rate • Nature of Reactants : The more bonds to brake the slower the reaction. In general, rxns involving covalent compounds are slower than rxns of ionic compounds • Temperature : ↑ T ↑ rate • Concentration : ↑ concentration ↑ rate • Gases - Pressure/Volume: ↑ P ↑ rate; ↓ V ↑ rate • Solids - Surface area : ↑ surface area ↑ rate • Catalyst: provides an alternative rxn pathway with lower E a increases the rate without being consumed
Q1: Level 1 (T16, LG5)Consider the following reaction:2H2O2(aq)2 H2O(l) + O2(g)When 1.0 g of KI(s) is added to 1MH2O2(aq), bubbles of O2(g) are produced at an increased rate and the temperature of the solution rises. When the reaction is complete, the mass of KI is 1.0 g. In this reaction KI is a _____. A.productB.transition stateC.intermediateD.catalystE.reactant
Q1: Solution Transition state : the arrangement of atoms found at the top of the potential energy “hill” (barrier) Intermediate : formed in one step of a reaction and then consumed in one of the following steps Catalyst : speeds up the reaction without being consumed. Added with reactants and remains unchanged after the reaction A. product B. transition state C. intermediate D. catalyst E. reactant Consider the following reaction: 2H 2 O 2 ( aq ) 2 H 2 O( l ) + O 2 ( g ) When 1.0 g of KI( s ) is added to 1 M H 2 O 2 ( aq ), bubbles of O 2 ( g ) are produced at an increased rate and the temperature of the solution rises. When the reaction is complete, the mass of KI is 1.0 g. In this reaction KI is a _____.
Q2a: Level 1 (T16, LG6) (0.5 pts) In the reaction coordinate diagram below X represents a ___. A. product B. intermediate C. catalyst D. reactant E. transition state Reaction coordinate Potential energy
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- Fall '08
- Chemical reaction, Rate equation, Rate Equations Review