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Each reaction has its own characteristic __. Its value depends o the __, especially the __. This __ dependence is expressed by the __.
- rate constant, kr
- conditions of the reaction
- temp
- temp dependence
- Arrhenius equation
- kr=Ae-Ea/RT
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Explain the components of the Arrhenius equation?
- A= a constant (the "frequency factor")
- Ea= activation energy
- R= the gas constant (8.314 J/ Kelvin-mole)
- T= the absolute temp
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The __ is the minimum kinetic energy the molecules must have to overcome the repulsions between their electron clouds when they collide. The exponential term e^(-Ea/RT) corresponds to the __ in which the particles have the __ needed to react.
- activation energy, Ea
- fraction of collisions
- minimum energy, Ea
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The __ accounts for the frequency of collisions and the fraction of collisions with the proper orientation for the reaction to occur. In most cases, only a small fraction of collisions occur between molecuels with enough ___ and with just the __ for reactions to occur. Far more collisions occur without enough __ or without the __, adn the molecules simply bounce off each other.
- frequency factor A
- speed
- right orientation
- kinetic energy
- proper orientation
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The __ implies that the rate of the reaction depends on the __ with kintetic energy of at least Ea.
- Arrhenius equation
- fraction of collisiosn
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Because the __ increases quickly when the temp is raised, it might seem that raising the temp would be a good way to save time by making reactions go faster. What is the problem, however?
- relative rate constant (krel)
- all reactions are accelerated, including all the unwanted side reactions (don't want that)
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The __ represents the energy differences between the __ and the __, the highest energy state in a molecular collision that leads to reaction.
- activation energy Ea
- reactants
- transition state
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In effect, __ is the barrier that must be overcome for the reaction to take place. The value of Ea is always __ and its magnitude depndds on the __ of the __.
- activation energy
- positive
- relative energy
- transition state
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The term __ implies that this configuration is the __ between the reactants and the products, and the molecules can either go on to products or return to reactants.
- transition state
- transition
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Unlike the reactants or products, a transition state is __ and cannot be __. It is not an __ because an __ is a species taht exists for some finite length of time, even if it very short.
- unstable
- cannot be isolated
- intermediate x2
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An __ has at least some stability, but the __ is a transient on the path from one __ to another.
- intermediate
- transition state
- intermediate
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Transition states have __ because bonds must begin to __ before other bonds can __.
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vertical axis of a reaction energy diagram is __.
horizontal axis?
- the total potential energy of all the species involved in the reaction
- reaction coordiate, which symbolizes the progress of the reaction, going from the reactants on the left to the products on the right
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highest point on the graph
what is activation energy on the graph?
- transition state
- energy difference between reactants and the transition state
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If a __ were added to the reaction, it would create a __ of lower energy, thereby lowering the __ and increasing the __. Addition of a __ would not change the enthalpies of the reactants and products, however, so the heat o reaction adn the equilibrium constant would be unaffected.
- catalyst
- transition state
- activation energy
- reaction rate
- catalyst
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Explain reactive intermediates?
stable as long as they don't collide with other atoms or molecuels
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energy maxima and energy minima
- e max: high points; unstable transition states
- e min: low points; intermediates
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In a multistep reaction, each step has its own characteristic rate. There can only be one overall reaction rate, however, and it is controlled by the __.
rate limiting (or rate determining) step
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In general, the __ of a multistep reaction is the __ adn it determines the overall rate.
- highest-energy step
- bottleneck
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