Quiz+Quiz+Trade

EXCELLENT GUYS! ~Ms. Fradkin

Q:Does a catalyst raise or lower the activation energy of a reaction, when changing the composition of the activated complex at the transition state? A:Lowers- the activated complex is lower in enthalpy than the uncatalyzed species.

Q: What does the potential energy diagram look like for an exothermic reaction? A: The products will have a lower potential energy than that of the reactants.

Q:Given the rate law Rate=k[A]3[B]0, how does the overall rate change if [A] is doubled? A: Ratex8

Q: What is the difference between average and instantaneous rate? And when would you use each of them? A: The average rate, is the average rate of the reaction, and the instantaneous rate is at a given point.

Q: Why is the activation energy of a reaction different with a catalyst and without a catalyst? And how is it different? A: The reaction without a catalyst has a higher activation energy than the reaction with a catalyst. This is due to the fact that the catalyst lowers the activation energy of the reaction by changing the composition of the activated complex at the transition state. The activated complex it forms is lower in enthalpy than the uncatalyzed species. Therefore, less external energy must be inputed to form it.

Q: If step B is 1000 times slower than step A, and step C is 500 times faster than step A, which one is the rate determining step? A: B

Q:Which reaction has a higher Ea barrier? a)2H2+O2--->2H2O (assuming rxn a is slower) b)2H2O->2H2+O2 A:Rxn a would be slower. This is because a slow reaction has a high activation energy barrier compared to a fast reaction.

Q: Create a potential energy diagram for the chemical reaction if the activation energy is 70kJ/mol and the enthal[y of the reaction is -120kJ/mol. (Forward direction) A: [[image:potential_energy_diagram.PNG width="360" height="225"]]

Q: What are each of the steps in a reaction mechanism called? A: Elementary Reactions.