Phase Diagrams Phase Diagram - Water Questions #1-5 refer to the phase diagram for water (shown to the right). 1. Which letter (A-E) represents the "triple point"? What does the "triple point 218-- mean? liquid A D solid 0.031 0.006- B. gas 2. At what pressure can water boil at room temperature (25 •C)? 0 25 100 Temperature (°C) 374 3. What phase is water found in at room temperature and 1 atmosphere pressure? 4. Water exists in what phase(s) at STP (Standard Temperature and Pressure)? 5. Which of the following phase changes (sublimation, deposition, melting, freezing, condensation, vaporization) occur along the curve BDE? Pressure (atm)

Study the following phase diagram of Substance X. 28- solid liquid 14. gas 0. 200 400 temperature (K) Use this diagram to answer the following questions. Suppose a small sample of pure X is held at 159. °C and 11.6 atm. What will be the state of the sample? (choose one) O Suppose the temperature is held constant at 159. °C but the pressure (choose one) is decreased by 7.7 atm. What will happen to the sample? Suppose, on the other hand, the pressure is held constant at 11.6 atm but the temperature is decreased by 194. °C. What will happen to the (choose one) sample? pressure (atm)

The normal boiling point of a liquid is 282 °C. At what temperature (in °C) would the vapor pressure be 0.230 atm? (AHvap = 28.5 kJ/mol) %3D 20

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Use the phase diagram of Substance X below to find the pressure at which the melting point of X is - 173. °C. 1.6- solid liquid 0.8- gas 100 200 temperature (K) Note: your answer must be within 0.1 atm of the exact answer to be graded correct. atm pressure (atm)

1. Freon-12 (CCl2F2) is banned as a refrigerant because it is harmful to the ozone. a. Sketch the phase diagram of CCl2F2 using the physical constants below Normal boiling point = -29.8 °C Normal melting point = -158 °C Critical temperature = 112 °C Critical pressure = 40.8 atm Triple point (2.42 ×10-6 atm, -157 °C) b. Calculate the heat required to bring 10.0g CCl2F2 from -29.8 °C as a liquid to the gas phase at 10.0 °C. (molar mass 120.91 g/mol) Cs (gas) = 0.074 kJ/mol·K AHvap = 20.1 kJ/mol AHfus = 4.14 kJ/mol

The pressure above a pure sample of solid Substance X at -5. °C is lowered. At what pressure will the sample melt? Use the phase diagram of X below to find your answer. 0.8- solid ol liquid 0.4 18 Ar gas 0. 200 400 600 temperature (K) Note: your answer must be within 0.05 atm of the exact answer to be graded correct. D atm pressure (atm)

Refer to the following phase diagram (not to scale!) for sulfur dioxide: P atm 78 1.00 0.0017 197.6 200.4 Choose all that apply T Kelvin A sample of sulfur dioxide at a pressure of 1.70×10-3 atm and a temperature of 266 K is compressed at constant temperature to a pressure of 83.7 atm. Which of the following are true? 263.1 430.7 The sample is initially a gas. The liquid initially present will vaporize. The final state of the substance is a liquid. The sample is initially a solid. One or more phase changes will occur.

Study the following phase diagram of Substance X. A B C E- F temperature (K) A C If a sample of pure X is solid, in which region must the temperature and pressure be? G H A Which line must the temperature and pressure have crossed if a gaseous sample of X is observed to condense? H А В Which is the critical point of X? E O F G он O O OO O C ш о O O O OlO O O OO O O O pressure (atm)