AP Chemistry Flashcards: Multistep Reaction Energy Profile

Study Multistep Reaction Energy Profile in AP Chemistry with focused flashcards that help you recognize the idea, recall the key rule, and apply it in practice-style prompts.

AP Chemistry

Multistep Reaction Energy Profile

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QUESTION
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Which part of the energy profile indicates an exothermic reaction?

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ANSWER

Products have lower energy than reactants. Energy is released when products are more stable than reactants.

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This deck focuses on Multistep Reaction Energy Profile, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

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Flashcard 1: Which part of the energy profile indicates an exothermic reaction?

Answer: Products have lower energy than reactants. Energy is released when products are more stable than reactants.

Flashcard 2: What is the effect of a catalyst on the rate of a reaction?

Answer: It increases the rate of the reaction. Lowers activation energy, allowing reaction to proceed faster.

Flashcard 3: How does a catalyst affect the transition state energy?

Answer: It lowers the energy of the transition state. Provides an alternative pathway with reduced energy barrier.

Flashcard 4: Identify which step is rate-limiting given activation energies.

Answer: Step with the highest activation energy. The slowest step has the largest energy barrier to overcome.

Flashcard 5: What is the significance of the highest peak in a multistep energy profile?

Answer: It represents the rate-determining step. The tallest peak controls the overall reaction rate.

Flashcard 6: Identify the intermediate in a multistep reaction energy profile.

Answer: A valley between peaks in the energy curve. Represents a temporarily stable species formed between reaction steps.

Flashcard 7: Identify the intermediate in a multistep reaction energy profile.

Answer: A valley between peaks in the energy curve. Represents a temporarily stable species formed between reaction steps.

Flashcard 8: What is the activation energy in a reaction energy profile?

Answer: The energy difference between reactants and the transition state. This represents the energy barrier that must be overcome for the reaction to proceed.

Flashcard 9: Find the energy of the transition state from a given profile.

Answer: Energy at the peak of the curve. The transition state occurs at the maximum energy point.

Flashcard 10: Which species in a reaction energy profile is typically unstable?

Answer: The transition state is typically unstable. It exists at maximum energy and quickly decomposes to products or reactants.

Flashcard 11: How is the stability of a species related to its energy in a profile?

Answer: Lower energy indicates greater stability. Species at lower energy positions are more thermodynamically stable.

Flashcard 12: Identify the part of the energy profile that represents the activation complex.

Answer: The peak of the energy curve. The activation complex is the same as the transition state.

Flashcard 13: Which reaction step is the slowest in a multistep process?

Answer: The rate-determining step. The step with highest activation energy limits overall reaction rate.

Flashcard 14: Which part of the energy profile indicates an endothermic reaction?

Answer: Products have higher energy than reactants. Energy is absorbed when products are less stable than reactants.

Flashcard 15: What does a reaction energy profile plot on the y-axis?

Answer: Potential energy. Energy represents the stored chemical potential energy of species.

Flashcard 16: State the relationship between activation energy and reaction rate.

Answer: Higher activation energy generally means slower reaction rate. Larger energy barriers require more thermal energy to overcome.

Flashcard 17: Identify the energy change if reactants have higher energy than products.

Answer: Exothermic reaction. Energy decreases from reactants to products, releasing heat.

Flashcard 18: Predict how a catalyst alters the energy profile of a reaction.

Answer: Lowers activation energy peaks. Catalyst reduces all activation energy barriers in the mechanism.

Flashcard 19: Identify the rate-determining step in a multistep reaction.

Answer: The step with the highest activation energy. The slowest step controls the overall reaction rate.

Flashcard 20: Identify the step with the smallest activation energy in a profile.

Answer: The step with the lowest peak. The shortest peak represents the easiest step to complete.

Flashcard 21: What is the nature of the reaction if ΔH>0\text{ΔH} > 0?

Answer: Endothermic reaction. Positive enthalpy change indicates energy absorption from surroundings.

Flashcard 22: What does the term 'reaction mechanism' refer to?

Answer: The step-by-step sequence of elementary reactions. Describes the detailed pathway from reactants to products.

Flashcard 23: State the formula to calculate the overall energy change in a reaction.

Answer: ΔE=EproductsEreactants\text{ΔE} = \text{E}_{\text{products}} - \text{E}_{\text{reactants}}. Final energy minus initial energy gives the net change.

Flashcard 24: Identify the transition state in a reaction energy profile.

Answer: The peak of the energy curve. It represents the highest energy point during the reaction pathway.

Flashcard 25: Evaluate if a reaction is exothermic from a given energy profile.

Answer: Reactants have higher energy than products. Final energy level below initial level indicates exothermic reaction.

Flashcard 26: What is the effect of a catalyst on the rate of a reaction?

Answer: It increases the rate of the reaction. Lowers activation energy, allowing reaction to proceed faster.

Flashcard 27: What does the height of the energy barrier in a profile indicate?

Answer: The activation energy of the reaction. Higher barriers require more energy to overcome for reaction.

Flashcard 28: State the formula to calculate the overall energy change in a reaction.

Answer: ΔE=EproductsEreactants\text{ΔE} = \text{E}_{\text{products}} - \text{E}_{\text{reactants}}. Final energy minus initial energy gives the net change.

Flashcard 29: Which factor does not affect the position of equilibrium in a chemical reaction?

Answer: Catalyst. Catalysts change reaction rate but not equilibrium position.

Flashcard 30: How does the energy profile change with a catalyst addition?

Answer: Lower peaks for each step. Catalyst provides alternative pathway with reduced energy barriers.

Flashcard 31: Identify the energy change if products have higher energy than reactants.

Answer: Endothermic reaction. Energy increases from reactants to products, absorbing heat.

Flashcard 32: What is the nature of the reaction if ΔH<0\text{ΔH} < 0?

Answer: Exothermic reaction. Negative enthalpy change indicates energy release to surroundings.

Flashcard 33: What does the area under a reaction energy profile curve represent?

Answer: It is not directly meaningful; focus on energy changes. The area has no physical significance in energy profiles.

Flashcard 34: What is the effect of a catalyst on the overall reaction energy change?

Answer: It does not affect the overall energy change. Catalysts only affect reaction rate, not thermodynamic properties.

Flashcard 35: Determine the intermediate energy level given a reaction profile.

Answer: Energy at the valley between peaks. Intermediates exist at local minima between transition state peaks.

Flashcard 36: Identify the peak with the highest energy in a multistep reaction profile.

Answer: The peak of the rate-determining step. The highest transition state determines the overall reaction rate.

Flashcard 37: What does a reaction energy profile plot on the x-axis?

Answer: Reaction progress. Shows how far the reaction has proceeded from start to finish.

Flashcard 38: What is the effect of temperature on the reaction rate?

Answer: Increasing temperature generally increases reaction rate. Higher thermal energy increases molecular collisions and reaction rates.

Flashcard 39: How is the stability of a species related to its energy in a profile?

Answer: Lower energy indicates greater stability. Species at lower energy positions are more thermodynamically stable.

Flashcard 40: Determine the overall reaction energy change from a provided profile.

Answer: Use ΔE=EproductsEreactants\text{ΔE} = \text{E}_{\text{products}} - \text{E}_{\text{reactants}}. Subtract reactant energy from product energy for net change.

Flashcard 41: Define the term 'enthalpy change' in a chemical reaction.

Answer: The heat change at constant pressure. Measures energy change when pressure remains constant during reaction.

Flashcard 42: What is the role of a catalyst in a multistep reaction energy profile?

Answer: It lowers the activation energy of the reaction. Provides an alternative pathway with a lower energy barrier.