Endo, Exo , and Phase diagrams

1. Endo, Exo, and Phase diagrams Think way back

2. Remember this image???

3. Endo vs. Exothermic • Endothermic—a reaction that requires energy to proceeds forward. • In endothermic reactions you begin in a low energy phase (solid or liquid) and change to a higher energy phase (liquid or gas). • Exothermic—a reaction that releases energy when is proceeds forward. • In exothermic reactions you begin in a high energy phase (gas or liquid) and change to a lower energy phase (liquid or solid). • Let’s take another look at that last image.

4. Note the colors

5. Endo or exothermic??? • I will use Excel to randomly pick a phase change. • You will tell me if the change is endothermic or exothermic. • Use your clickers to respond A= Exothermic B= Endothermic

6. Phase Diagrams

7. Which of the following transitions represents an increase in temperature while the pressure remains the same? 1) A B 3) FB 2) C B 4) BA

8. Which of the following transitions represents an increase in pressure while the temperature remains the same? 1) A B 3) FB 2) C B 4) BA

9. Which of the following transitions would result in MELTING? 1) A B 3) FB 2) C A 4) BA

10. Which of the following transitions would result in BOILING? 1) A B 3) FB 2) C D 4) DE

11. Which of the following transitions would result in CONDENSATION? 1) A B 3) FB 2) C D 4) DE

12. Which of the following transitions would result in SUBLIMATION? 1) A B 3) CE 2) C D 4) ED

13. Which of the following transitions would result in MELTING followed by BOILING? 1) A B 3) CE 2) C D 4) CF

14. Which of the following transitions would NOT result in MELTING? 1) A B 3) AD 2) C B 4) DB

15. Which of the following transitions would result in a phase change? 1) A B 3) BD 2) C A 4) EF