1. Topic: Heating Curves for pure substance Do Now: What is the difference between a mixture and a pure substance?

2. Review: Name the phase change S  L L  G G  L L  S S  G G  S Melting (fusion) Boiling (vaporization) condensation Freezing (solidification) sublimation deposition

3. REVIEW: All Phase changes accompanied by energy changes

4. B D  E C  B E  D MELTING Vaporization (boiling) FREEZING Condensation EXO ENDO

5. Time Temperature IVV Solid Solid & Liquid Liquid Liquid & Gas Gas K.E.  K.E.↔ P.E.↔ P.E.  Melt pt. Boil pt. ● ●

6. Time Temperature I II IIIIVV Solid Solid & Liquid Liquid Liquid & Gas Gas K.E.  K.E.↔ P.E.↔ P.E.  Melt pt. Boil pt. ● ● Freezing pt. ●

7. B D  E C  B E  D MELTING Vaporization (boiling) FREEZING Condensation Melting point/Freezing Point Boiling Point

8. Melting & Boiling Points (start of the phase change) Plateaus = Phase changes = PE changes –always given as temp (˚C, K) WHY IS IT CALLED A POINT?

9. During Phase changes More than one phase is present –Melting : solid and liquid –Boiling: liquid and gas (lets check out a tiger animation) temperature is constant:  T=0 –There is no change in temp!!!!! ***NOTE: if 2 phases are present, temp is constant

10. QUICK QUESTION: What happens to temperature as heat is added to boiling water? Nothing, temp doesn't’t change b/c 2 phases are present –  temp will change when only 1 phase is present!

11. PAGE 13 answer 3-8 3. MP = _________ BP=_______ 7. When is the kinetic energy of the sample the greatest? 8. Given a constant heating rate of 150 Joules per minute, how many joules of heat must the sample absorb to melt all of the sample? To vaporize all of the sample? GAS phase 150 J9 minutes= 1350 Joules minute 150 J30 minutes= 4500 Joules minute 9 30 70 °C 150 °C

12. What do you think a cooling curve would look like?