(b) Consider the phase diagram for elemental carbon: 700 Pressure (kbars) 600 500 400 300- 200 Solid 100- O III fee Diamond 1000 Liquid hep Graphite 3000 Temperature Explain what happens as carbon at 2500° and atmospheric pressure is cooled to 1150⁰ and the pressure is raised to 500 atm.

Construct a phase diagram for a substance. Label: S (solid), L (liquid), G (gas). Curves/ Lines of equilibrium between solid-gas, liquid-gas, and solid-liquid. (It need not to be scaled)            T(°K)    P (atm) Triple point 55 K 0.50 atm Normal meting point 68 K 1 atm Normal boiling point 183 K 1 atm Critical Point 218 K 50 atm

(2) Sublimation. Figures below represent the phase diagrams for water and carbon dioxide. (a) Describe the difference in sublimation behavior under the pressure and temperature conditions prevailing on Earth. (b) How would you explain the sublimation of the polar ice caps on Mars during the Martian Summer? 217.7 METING FREZING Normal melting point Solid -Normal boiling point Liquid VAPOURISON COKDENSATION Gas 0.006 SUBLIMATION DEPOSITION 100 374.4 Temperature ("C) Pressure (atm)

Consider the phase diagram of kryptonite shown below. بلا P (atm) 10 20 30 40 50 60 70 T (deg. Celsius) As the temperature of kryptonite is decreased from 40° C to 20° C at 1 atm pressure, what phase change occurs? sublimation condensation O O melting O freezing O boiling

Organic molecules change phases above 300°C. O True O False

Describe the major features of the phase diagram?

Substance X is known to exist at 1 atm in the solid, liquid, or vapor phase, depending on the temperature. Additionally, the values of these other properties of X I have been determined: melting point enthalpy of fusion temperature (°C) 120- 110- 100- 90- 80 70- 60- You may also assume X behaves as an ideal gas in the vapor phase. Suppose a small sample of X at 20 °C is put into an evacuated flask and heated at a constant rate until 10.0 kJ/mol of heat has been added to the sample. Graph the temperature of the sample that would be observed during this experiment. density 50+ 40 30- 20 65. °C 10.00 kJ/mol 3 2.80 g/cm³ (solid) 2.30 g/mL (liquid) 0 heat added (kJ/mol) 8 9 boiling point enthalpy of vaporization 10 heat capacity P 100. °C X 21.00 kJ/mol -1 38. J K mol (solid) 29. J.K¹ mol 48. J.K¹ mol 1 (liquid) (vapor) 2 00 ola Ar B

Consider the phase diagram shown. What is the normal sublimation point at 1 atm? Pressure (not to scale) 72.9 atm 5.1 atm 1 atm O 0°C O 100°C -56.7 °C 31°C -78.5 °C SOLID LIQUID GAS -78.5 °C -56.7 °C Temperature (not to scale) 31 °C

Name: Period: Date: Unit 14: Thermodynamics Part 1: Phase Diagrams Below is a Phase Diagram for WATER. Critical point 225 atm 1 atm Water (liquid) Ice Pressure (solid) Water vapor (gas) 0.006 atm Triple point 0.01° C 100° C 3740 C Temperature Drawing is not to scale 1. The point where all three phases of matter exist is called the 2. The triple point for water is at and 3. The temperature above which a substance cannot be a liquid is called the 4. The critical point for water is at and 5. Normal freezing and boiling points always occur at atm. 6. Water's freezing point is and its boiling point is 7. What is the state of water at 200°C and 200 atm? 8. Beginning at 1 atm and 1.0°C, what phase change occurs when the pressure drops to 0.004 atm? 9. What phase change occurs if steam at 300°C and 1.5 atm cools to 50°C at constant pressure? 10. What phase change occurs if water at 50°C and 1.5 atm is placed in a vacuum at a pressure of 0.002 atm?

Draw the phase diagram of carbon dioxide and explain the meaning of three regions and lines.