AP Chemistry · Unit 9: Thermodynamics and Electrochemistry
9.7 Coupled Reactions
In short
You must understand that an external source of energy can be used to make a thermodynamically unfavorable process occur. Examples include using electrical energy to drive an electrolytic cell or charge a battery, and using light to drive the overall conversion of carbon dioxide to glucose in photosynthesis.
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What else do you need to know about Coupled Reactions?
Additionally, a desired product can be formed by coupling a thermodynamically unfavorable reaction that produces that product to a favorable reaction (e.g., the conversion of ATP to ADP in biological systems). You should know that in a coupled system, the individual reactions share one or more common intermediates, and the sum of the individual reactions produces an overall reaction that achieves the desired outcome and has ΔG° < 0.
How is Coupled Reactions tested on the exam?
You are assessed on your ability to explain the degree to which a model or representation describes the connection between particulate-level properties and macroscopic properties (Suggested Skill 4.D). Questions may require you to analyze models of coupled reactions or systems where external energy sources drive thermodynamically unfavorable processes.
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Coupled Reactions: common questions
What do you need to know about Coupled Reactions for AP Chemistry?
You must understand that an external source of energy can be used to make a thermodynamically unfavorable process occur. Examples include using electrical energy to drive an electrolytic cell or charge a battery, and using light to drive the overall conversion of carbon dioxide to glucose in photosynthesis.
How is Coupled Reactions tested on the AP Chemistry exam?
You are assessed on your ability to explain the degree to which a model or representation describes the connection between particulate-level properties and macroscopic properties (Suggested Skill 4.D). Questions may require you to analyze models of coupled reactions or systems where external energy sources drive thermodynamically unfavorable processes.
Where does Coupled Reactions fit in AP Chemistry?
Coupled Reactions is topic 9.7 in Unit 9: Thermodynamics and Electrochemistry of AP Chemistry.
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