Science Starter (Week 15, Day 2, 5/11/16) HW 7.4 ON DESK In the graph to the right, in which areas is phase energy increasing? Thermal energy? A 300g sample of 25C water increases in temperature to 115C. Draw the heating/cooling curve What is specific heat? What is frostbite?

SWBAT describe sublimation Objective SWBAT describe sublimation SWBAT read phase change diagrams and describe the pressures and temperatures associated with phase changes

Homework: Worksheet 7.5 Phase Change Diagrams Agenda Science Starter Notes: Phase Change Diagrams Dry Ice Lab HW Time Homework: Worksheet 7.5 Phase Change Diagrams

TEST FRIDAY ON UNIT 7!!!

Unit 7: Heat and Energy Phase Change Diagrams

Phase change depends upon the temperature and pressure. Phase Change Diagrams Phase change depends upon the temperature and pressure. 1. Solids = low temperature and high pressure 2. Liquids = medium temperature and medium pressure 3. Gases = high temperature and low pressure Triple Point: Where a substance can be either a solid, liquid or a gas Critical Point: The temperature of a gas is so high that you cannot compress it to a liquid.

Discussion Intro to Phase Diagrams: What state of matter would you expect at a very high temperature? What state of matter would you expect at a very low temperature? What state of matter would you expect at a very high pressure? What state of matter would you expect at a very low pressure?

Consensus The triple point is where solid liquid and gas all exist at the same time. Where do you think that is on this graph? What do all of the lines represent on the graph? For example if I cross the line from A to B (solid to a gas) what happened?

Conclusion Looking at your answers, what state of matter would you expect if temperature was somewhere in the middle? Looking at your answers, what state of matter would you expect if pressure was somewhere in the middle?

Phase Diagram Practice 1) If I had a quantity of this substance at a pressure of 1.25 atm and a temperature of 300oC and lowered the pressure to 0.25 atm, what phase transition(s) would occur?

Phase Diagram Practice 2) If I had a quantity of this substance at a pressure of 0.75 atm and a temperature of -1000 C, what phase change(s) would occur if I increased the temperature to 6000 C? At what temperature(s) would they occur?

Background Information Dry Ice - solid form of carbon dioxide gas. Sublimation – The transition of a substance from the solid phase to the gas phase without going through the liquid phase.

must keep goggles on at all times. Mini Lab: Dry Ice Rules: must keep goggles on at all times. No goggles = book work and/or burned eyes Do not touch the dry ice with your hands or put it on anybody – it is too dangerous and I will write you a referral for intent to commit bodily harm (10 days)

Data / Analysis: Read and follow the procedures at lab station. Mini Lab: Dry Ice Data / Analysis: Read and follow the procedures at lab station.