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Org 1 Review - Thermodynamics

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saruxoha's version from 2017-07-19 15:14

Section

Question Answer
True or false: by examining the delta G of a reaction you can get useful information about the reaction rate. False - even if a reaction is highly thermodynamically favorable, that doesn't tell you about the rate of the reaction. You need to know the activation energy for that.
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True or false: by examinine the activation energy of a process you can get useful information about the rate.
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True - the activation energy gives you an accurate idea of the rate.
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The hammond postulate: In an exothermic reaction the transition state will tend to resemble the _____ while in an endothermic reaction the transition state will tend to resemble the _______
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Exothermic reaction - transition state resembles reactants, while in an endothermic reaction the transition state tends to resemble the products.
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The overall delta H for a given reaction is -200 kJ/mol.
1) what does delta H mean
2) what's the word for a process that has a negative delta H?
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1) delta H means enthalpy

2) this is exothermic
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True or false: any reaction in which bonds are broken will have an activation energy >0, even if a stronger bond is formed.
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True

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True or false: the activation energy of a reaction will be the activation energy of the slowest step.
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True

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True or false: the activation energy of a step where *just* bonds are broken is equal to the enthalpy of that bond (example: Br2 --> 2 Br•)
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True

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True or false: the activation energy for the formation of a new bond from two free radicals is zero.
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True

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What's the difference between a transition state and an intermediate?

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Transition state - partial bonds, not potentially isolable (a local maximum in the energy diagram); intermediate is a local minimum, potentially isolable. A good example of an intermediate is the carbocation in the SN1 or E1 reaction.
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Which product is more stable: the thermodynamic product or the kinetic product?
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The "thermodynamic product" is more stable. The "kinetic product" is the one that is formed the fastest.
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More stable = "higher energy" or "lower energy" ? More stable = lower energy (analogous to height)
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Org 1 Review - Thermodynamics
Org 1 Review - Free Radicals
Org 1 Review - Reactions of Alcohols
Org 1 Review - Alkynes
Org 1 Review - Substitution and Elimination
Org 1 Review - Reactions of Double Bonds
Org 1 Review - Stereochemistry
Org 1 Review - Conformations
Org 1 Review - Structure and Bonding