Organic Chemistry : Reaction Energetics and Kinetmatics

Study concepts, example questions & explanations for Organic Chemistry

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Example Questions

Example Question #1 : Reaction Energetics And Kinetmatics

With what mechanism do catalysts speed up a reaction?

Possible Answers:

They increase the  of the reaction.

They raise the activation energy of the reaction.

They lower the  of the reaction.

They lower the activation energy of the reaction.

Correct answer:

They lower the activation energy of the reaction.

Explanation:

Regarding chemical reactions, the activation energy is the minimum energy which must be available in a chemical system in order for reactants to participate in a chemical reaction. Catalysts speed up reactions by lowering this minimum energy. Raising it would have the opposite effect. Catalysts do not alter the  of a reaction. Remember this--it is a common error to make!

Example Question #2 : Reaction Energetics And Kinetmatics

What kinetic equation describes the rate of an E1 process?

Possible Answers:

None of these

Correct answer:

Explanation:

Most organic reactions are carried out in multiple steps. The rate equation can be derived from the process that occurs in the slowest step of the mechanism. An E1 reaction's slow step is when a leaving group separates from the hydrocarbon and a carbocation is formed. The only reactant in this step is one molar equivalent of the hydrocarbon. Thus, the rate equation only depends on that substance. The molar equivalent determines the exponent of each reactant in the equation.

Example Question #1 : Reaction Energetics And Kinetmatics

Generally, when compared to the rate of inorganic reactions, the rate of organic reactions is __________.

Possible Answers:

Slower, because organic compounds are ionic

Faster, because organic compounds contain covalent compounds

Slower, because organic compounds contain covalent bonds

Faster, because organic compounds are ionic

Correct answer:

Slower, because organic compounds contain covalent bonds

Explanation:

By and large, organic compounds contain mainly covalent bonds. Covalent bonds are typically harder to break, which is why organic reactions happen at a relatively slower rate than inorganic reactions.

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