Period Date 13 IMF\'s, Liquids, and Solids BOILING PRACTICE Vapor Pressures of V
ID: 566102 • Letter: P
Question
Period Date 13 IMF's, Liquids, and Solids BOILING PRACTICE Vapor Pressures of Various Liquids Ethyl Methyl Benzene Salicylate Carbon IemperatureAlcohol B Water Tetrachloride 19 15 12.2 17.3 23.6 32.2 43.9 59.0 78.8 103.7 9.2 12.8 17.5 23.8 15 71 25 30 94 143 176 42.2 55.3 147 182 225 271 325 389 462 547 643 753 877 1020 1180 40 45 263 174.0 222.2 280.6 352.7 448.8531 542.5 666.1 812.6 986.7 1187 1420 1.41 1.90 2.52 3.40 4.41 5.90 7.63 9.93 12.8 92.5 118.0 149.4 190.0 233.7 289.1 60 451 622 843 75 80 85 90 95 100 433.6 525.8 633.9 760.0 1360 1122 1270 1463 1693.3 Exl. A beaker of benzene (CsHe) is at room temperature (20° C). What is its vapor pressure?mmHg Ex2. All of the liquids are heated to 80°C, circle those that will be boiling when the air pressure is 760 mmHg. Ex3. I the tempernature remains unchanged,but the pressure above the liquids is reduced to 700 mmitg,circle thos Is this vapor pressure large enough to cause the benzene to boil at sea level? ethyl alcohol benzene methyl salicylate water carbon tetrachloride substances that will be boiling. water carbon tetrachloride ethyl alcohol benzene methyl salicylateExplanation / Answer
1) Refer to the table above. The vapor pressure of benzene at 20°C is 91 mmHg.
The temperature at sea level is around 15°C and the corresponding vapor pressure is 71 mmHg. However, the normal boiling point of a material is when the vapor pressure equals the atmospheric pressure (1 atm) which is equivalent to 760 mmHg. The vapor pressure exceeds the atmospheric pressure when the temperature is around 80°C; hence, benzene will not boil at the said temperature.
2) The air pressure is 760 mmHg which is equivalent to 1 atm pressure. The normal boiling point of a liquid is the temperature when the vapor pressure equals 1 atm. At 80°C, the vapor pressures for ethyl alcohol, benzene and carbon tetrachloride are higher than or almost equal to 1 atm; hence, these three liquids will boil.
3) The temperature is held at 70°C, but the air pressure is reduced to 700 mmHg. At the said temperature, the vapor pressure of carbon tetrachloride is close to the air pressure and hence, only carbon tetrachloride will boil.