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 describe entropy as how spread out a system’s energy is, and link higher entropy to less energy being available to do work. (Guide: “Entropy: how spread out the energy is”; Practice Q7d)
- I can give everyday examples of concentrated energy spreading out by itself. (Guide: “Which way do things happen?”)
- I can state the second law for an isolated system, including when total entropy stays constant. (Guide: “The second law”; Practice Q1)
- I can explain what makes a process reversible and why every real process is irreversible. (Guide: “The second law”; Practice Q7c)
- I can explain why entropy is a state function, and why ΔS = 0 for a system that completes a cycle. (Guide: “Entropy is a state function”; Practice Q3, Q7b)
- I can explain why an isolated system moves toward equilibrium and why its entropy is greatest there. (Guide: Figure 1; Practice Q6c)
Skills
- I can sketch how the temperatures and the total entropy of two objects change as they reach equilibrium. (Guide: Figure 1; Practice Q6a, Q6b)
- I can draw a system boundary and say whether the system is isolated or closed. (Guide: Figure 2; Practice Q2)
- I can combine an energy calculation (Q = mcΔT or ΔU = Q + W) with a statement about entropy. (Guide: Worked example 1; Practice Q5, Q7a)
Reasoning
- I can explain how a closed system’s entropy can decrease without breaking the second law. (Guide: “Isolated systems and closed systems”; Practice Q2, Q6d)
- I can compare two paths between the same states: same ΔS for the system, different effects on the surroundings. (Guide: Worked example 2; Practice Q3, Q4)
- I can use the second law to explain why a process that conserves energy still never happens in reverse. (Practice Q5d)
- Stretch (background): I can explain why no engine can turn all of the energy it takes in by heating into work. (Guide: background note on engines; Practice Q7d)
All ticked? You have finished this unit. Move on to Unit 10, Electric Force, Field, and Potential, starting with Topic 10.1, Electric Charge and Electric Force, or return to the course roadmap.