101.325 kPa = 760.0 torr = 760.0 mmHg = 1.00 atm = atmospheric pressure Name _____________________________Pd_____ Vapor Pressure and Boiling The following graph shows vapor pressure curves for two substances, A and B. 800 700 600 Hg) 500 400 A 300 Pressure (mm B 200 100 0 10 20 30 40 50 60 70 80 90 100 110 120 Temperature (°C) Answer the following questions. 1. What is the vapor pressure of A at 35 °C? 1. __________________ 2. What is the vapor pressure of B at 35 °C 2. __________________ 3. At what temperature is the vapor pressure of A 800 mm?` 3. __________________ 4. What is the vapor pressure of B at this temperature? 4. __________________ 5. At what temperature is the vapor pressure of A equal to your 5. __________________ answer to Questions 4? 6. What is meant of “normal boiling point? 6. __________________ ___________________________________________________________________________ 7. What is the normal boiling point of A? 7. __________________ 8 What is the normal boiling point of B? 8. __________________ 9. At what temperature would A boil if atmospheric pressure 9. __________________ were 700 mm? 10. What would the atmospheric pressure have to be in order for B to 10. __________________ boil at the temperature you gave as your answer to Question 9? CHCl3 CCl4 H2O A and B are temperatures; The others are points on the graph 101.325 kPa G 100 E F 80 B Gas Liquid Gas 60 C D A Liquid 40 Solid Liquid Solid Vapor (kPa) Pressure 20 Temperature Energy Figure 2 0 20 40 60 80 100 Temperature (°C) Figure 1 Use Figure 1 to answer the following questions. 1. What will the boiling point of CHCl3 be when the atmospheric 1. __________________ pressure exerted on its surface is 101.325 kPa? 2. What is the normal boiling point for CCL4? 2. __________________ 3. What is the pressure when water boils at 70 °C? 3. __________________ 4. Which liquid on the graph has molecules that exert the strongest 4. __________________ attractive forces with each other? 5. Does increasing the temperature of a liquid cause its vapor pressure 5. __________________ to increase or decrease? 6. Which of the liquids in Figure 1 would be easiest to evaporate? 6. __________________ Use Figure 2 to answer the following questions. 7. Identify the point of the graph where each of the following occurs. _______ a. melting begins ______ c. boiling begins _______ b. freezing begins ______ d. condensation begins 8. Does the substance give off or take in heat as it goes from D to C? 8. __________________ Name _____________________________ Date _____________________ Per. _____ Vapor Pressure and Boiling The following graph shows vapor pressure curves for two substances, A and B. 800 700 600 500 400 A 300 Pressure (mm Hg) B 200 100 0 10 20 30 40 50 60 70 80 90 100 110 120 Temperature (°C) Answer the following questions. 1. What is the vapor pressure of A at 35 °C? 1. __________________ 150 mm Hg 2. What is the vapor pressure of B at 35 °C 2. __________________ 75 mm Hg 3. At what temperature is the vapor pressure of A 800 mm?` 3. __________________ 75 °C 4. What is the vapor pressure of B at this temperature? 4. __________________ 225 mm Hg 5. At what temperature is the vapor pressure of A equal to your 5. __________________ 45 °C answer to Questions 4? 6. What is meant of “normal boiling point? 6. __________________the temperature ___________________________________________________________________________at which a liquid evaporates when the external pressure is 1 atmosphere 7. What is the normal boiling point of A? 7. __________________ 74 °C 8 What is the normal boiling point of B? 8. __________________ 118 °C 9. At what temperature would A boil if atmospheric pressure 9. __________________ 73 °C were 700 mm? 10. What would the atmospheric pressure have to be in order for B to 10. __________________ 225 mm Hg boil at the temperature you gave as your answer to Question 9? CHCl3 CCl4 H2O A and B are temperatures; 101.325 kPa The others are points on the graph 100 G 80 E F B Gas 60 Liquid Gas C D A 40 Liquid Solid Liquid Vapor (kPa) Pressure 20 Solid Temperature Energy 0 20 40 60 80 100 Figure 2 Temperature (°C) Figure 1 Use Figure 1 to answer the following questions. 1. What will the boiling point of CHCl3 be when the atmospheric 1. __________________ 60 °C pressure exerted on its surface is 101.325 kPa? 2. What is the normal boiling point for CCl4? 2. __________________ 75 °C 3. What is the pressure when water boils at 70 °C? 3. __________________ 35 kPa 4. Which liquid on the graph has molecules that exert the strongest 4. __________________H2O attractive forces with each other? 5. Does increasing the temperature of a liquid cause its vapor pressure 5. __________________increase to increase or decrease? 6. Which of the liquids in Figure 1 would be easiest to evaporate? 6. __________________CHCl3 Use Figure 2 to answer the following questions. 7. Identify the point of the graph where each of the following occurs. _______C a. melting begins ______E c. boiling begins _______D b. freezing begins ______F d. condensation begins 8. Does the substance give off or take in heat as it goes from D to C? 8. __________________gives off energy .