Chemistry Year 12 - Module 5 - Lesson 2
Reversibility, Non-Equilibrium Systems & Entropy
1. Key Ideas
Fritz Haber's discovery that nitrogen and hydrogen gas could be converted to ammonia — reversibly — changed the course of human history. The reaction that feeds half the world's population works precisely because it doesn't go all the way to completion.
- The thermodynamic spectrum from irreversible to reversible reactions
- Why large negative ΔG° means the reaction goes to completion
2. Success Criteria
By the end, you should be able to:
- The thermodynamic spectrum from irreversible to reversible reactions
- The connection between the magnitude of ΔG° and the position of equilibrium
- Why at equilibrium, ΔG = 0
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. Explain this lesson goal in your own words: "The thermodynamic spectrum from irreversible to reversible reactions". Use one specific example from the lesson.
2. Apply this idea to a new example: "The connection between the magnitude of ΔG° and the position of equilibrium". Show your reasoning clearly.
3. Analyse why this idea matters for understanding Reversibility, Non-Equilibrium Systems & Entropy: "Why at equilibrium, ΔG = 0".
6. Extend: Apply the Idea
A student gives a memorised answer about Reversibility, Non-Equilibrium Systems & Entropy but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Reversibility, Non-Equilibrium Systems & Entropy?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Reversibility, Non-Equilibrium Systems & Entropy?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.