- 5 Why Doesn T The Vapor Pressure Of A Liquid Depend On The Amount Of Liquid And Vapor Present 6 In Figure 13 5 In Wh 1 (162.26 KiB) Viewed 86 times
5. Why doesn't the vapor pressure of a liquid depend on the amount of liquid and vapor present? 6. In Figure 13.5, in which case, (a), (b) or (c) will the atmosphere above the liquid reach a point of saturation? 1. Suppose a solution of ethyl ether and ethyl alcohol is placed in the closed bottle in Figure 13.5. (Use Figure 13.7 for information on the substances.) (a) Are both substances present in the vapor? (b) If the answer to part(a) is yes, which has more molecules in the vapor? Explain why rubbing alcohol warmed to body temperature still feels cold when applied to your skin. The vapor pressure at 20°C for the following substances is methyl alcohol 96 torr acetic acid 11.7 tort benzene 74.7 torr bromine 173 torr water 17.5 torr carbon tetrachloride 91 torr mercury 0.0012 torr toluene 23 ton 14. Use the graph in Figure 13.7 to find the following: (a) boiling point of water at 500 tort (b) normal boiling point of ethyl alcohol (c) boiling point of ethyl ether at 0.50 atm 15. Suggest a method whereby water could be made to boil at 50°C. 16. Explain why a higher temperature is obtained in a pressure cooker than in an ordinary cooking pot. (17. What is the relationship between vapor pressure and boiling point? (18. The boiling point of ammonia, NH,, is -33.4°C and that of sulfur dioxide, SO, is -10.0°C. Which has the higher vapor pressure at -40°C? 19. Explain what is occurring physically when a substance is boiling. 20. At what specific temperature will ethyl ether have a vapor pressure of 760 ton? 21. Compare the potential energy of the three states of water shown in Figure 13.11. 22. Consider Figure 13.8. (a) Why is line BC horizontal? What is happening in this interval? (b) What phases are present in the interval BC? (c) When heating is continued after point C, another horizontal line, DE, is reached at a higher temperature. What does this line represent? 23. Account for the fact that an ice-water mixture remains at 0°C until all the ice is melted, even though heat is applied to it. 24. Which contains less energy: ice at 0°C or water at 0°C? Explain. 25. Why does a boiling liquid maintain a constant temperature when heat is continuously being added? (a) Arrange these substances in order of increasing rate of evaporation (b) Which substance listed has the highest boiling point? the lowest? 20. On the basis of the kinetic-molecular theory, explain why vapor pressure increases with temperature.