Organic Reaction Pathways and Energy Profiles
Chemistry ⇒ Carbon and Organic Chemistry
Organic Reaction Pathways and Energy Profiles starts at 11 and continues till grade 12.
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A reaction has an activation energy of 50 kJ/mol and a ΔH of -20 kJ/mol. Is the reaction exothermic or endothermic?
Describe the difference between a reaction intermediate and a transition state in an organic reaction pathway.
Describe the effect of a catalyst on the activation energy and the overall enthalpy change of a reaction.
Describe the main difference between homolytic and heterolytic bond cleavage in organic reactions.
A reaction has an activation energy of 50 kJ/mol and a ΔH of -20 kJ/mol. Is the reaction exothermic or endothermic?
A certain organic reaction proceeds via a two-step mechanism. The first step is endothermic and slow, while the second step is exothermic and fast. Explain, with reference to the energy profile, which step determines the overall rate and why.
A reaction has two possible pathways: one with a lower activation energy but less negative ΔH, and one with a higher activation energy but more negative ΔH. Which pathway is favored kinetically, and which is favored thermodynamically?
Consider a reaction where the energy profile shows a single peak and no intermediates. Which type of mechanism is most likely? (1) Stepwise (2) Concerted (3) Radical chain (4) Multi-step
A reaction proceeds via a carbocation intermediate. Which mechanism is most likely? (1) SN2 (2) SN1 (3) E2 (4) Free radical substitution
Which of the following best describes a leaving group in a substitution reaction? (1) A group that donates electrons (2) A group that accepts electrons (3) A group that departs with a pair of electrons (4) A group that remains attached to the substrate
Which of the following best describes a nucleophile? (1) Electron pair donor (2) Electron pair acceptor (3) Proton donor (4) Proton acceptor
Which of the following best describes an exothermic reaction pathway? (1) The products have higher energy than the reactants. (2) The products have lower energy than the reactants. (3) The activation energy is zero. (4) The reaction does not require a catalyst.
Fill in the blank: In a reaction energy profile, the valley between two peaks represents a(n) __________.
Fill in the blank: In an addition reaction to an alkene, the π bond is broken and two new __________ are formed.
Fill in the blank: In an E2 elimination reaction, the base removes a __________ from the β-carbon.
Fill in the blank: The rate of an SN1 reaction depends on the concentration of the __________ only.
True or False: In a reaction energy profile, the activation energy is the difference in energy between the reactants and the transition state.
True or False: In an E1 elimination reaction, the formation of the carbocation intermediate is the rate-determining step.
True or False: In an SN2 reaction, the reaction rate depends only on the concentration of the nucleophile.
True or False: The energy profile of a multi-step reaction will show multiple peaks, each corresponding to a transition state.
