Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can explain why a process with ΔG° > 0 can still be made to happen if free energy is supplied. (Guide: “Unfavourable does not mean impossible”)
- I can describe how electrical energy drives electrolysis and battery charging, and how light drives photosynthesis. (Guide: “Driving a process with an outside energy source”; Practice Q3)
- I can tell the difference between supplying activation energy (a spark, a catalyst) and supplying the free energy an unfavourable process needs. (Practice Q1, Q3)
- I can explain what a common intermediate is and why coupled reactions must share one. (Guide: “Coupled reactions and the common intermediate”; Practice Q1, Q7)
- I can describe how cells use ATP hydrolysis to drive unfavourable reactions. (Guide: “Coupling in living things: ATP”)
Calculation
- I can reverse or scale an equation so that the intermediate cancels, changing ΔG° correctly. (Practice Q2)
- I can add coupled reactions and their ΔG° values to find the overall reaction and its ΔG°. (Guide: Worked example 1; Practice Q2, Q6)
- I can find how many ATP must be hydrolysed to make an overall process favourable. (Guide: Worked example 2; Practice Q4)
- I can multiply equilibrium constants of coupled steps and convert between K and ΔG°. (Guide: “What happens to K?”; Practice Q4, Q5)
- I can estimate the minimum light energy needed to drive a reaction. (Guide: Worked example 3)
Reasoning
- I can judge whether a proposed coupling will work, using the sign of the overall ΔG°. (Practice Q6)
- I can explain why a favourable reaction in a separate container does not drive an unfavourable one. (Practice Q7)
- I can explain why a negative overall ΔG° does not mean the reaction is fast. (Guide: Common misconceptions)
All ticked? Move on to Topic 9.8, Galvanic (Voltaic) and Electrolytic Cells, or return to the course roadmap.