Safety boundary
Use supplied graphs and calculations only. No new reactive chemistry is required.
Explicit chemistry instruction
Preserve raw thermodynamic data before calculating ΔG.
Calculate ΔG across several temperatures and graph the result.
Compare predicted sign changes with the modeled process behavior and discuss uncertainty.
Vocabulary: thermodynamic dataset; temperature; ΔG; sign change; uncertainty.
Worked example
If ΔG crosses from positive to negative between 280 and 320 K, the crossover region is evidence of temperature-dependent favorability.
Guided question
What graph best shows a crossover temperature?
Independent work
- Preserve raw ΔH/ΔS/T data.
- Calculate ΔG values.
- Graph ΔG versus T.
- Estimate crossover and uncertainty.
Investigation / Data Lab
Preserve raw thermodynamic data, calculations, graph, crossover estimate, uncertainty, and one revision.
Misconception check
A calculated sign change should not be reported with more precision than the input data support.
Formative check
What indicates the crossover temperature on a ΔG-versus-T graph?
Reveal response
Where the graph crosses ΔG=0.
Mentor evidence conference
Ask Archaemenes to audit signs, units, thermodynamic conditions, and whether rate/direction are being kept distinct.
Teacher guidance
Foundation: Use a calculation table.
Core: Graph and interpret ΔG.
Extended: Estimate uncertainty in crossover.