1. at 34.9 degrees Celsius, the vapor pressure of ethanol is 115torr. Calculate

Question

1. at 34.9 degrees Celsius, the vapor pressure of ethanol is 115torr. Calculate the temperature (in Celsius) required to increasethe vapor pressure of ethanol to 760 torr, given that the heat ofvaporization <>Hvap of ethanol is 40.5 kJ/mol.

correct answer: 77 degrees Celsius

2. A sample of carbon dioxide gas at 125 degrees Celsius and 248torr occupies a volume of 275 L. What will the gas pressure be ifthe volume is increased to 321 L at 125 degrees Celsius?

correct answer: 212 torr

please show me step by step how to solve these, i got a differentanswer than the correct one. thanks in advance :)

Explanation / Answer

      1 . According toArrhenius equation                            ln P2 / P1 = (Hvap /R ) ( 1 /T1 - 1/ T2)                                 T1 = 34.9 oC = 307.9 K ,   P1 =115 torr                      T2 = ?                               P2 = 760 torr                     Hvap= 40.5 kJ/mol = 40.5 x 103 J /mol                ln (760 / 115) =   (40.5 x103 / 8.314 ) ( 1/ 307.9 K - 1 / T2 )              T2 = 349.6 K = 76. 65oC           2 ) At constant temperature  P1V1 = P2 V2                         P1 = 248 torr        V1 = 275 L                   P2 =?                    V2   = 321 L                  248 * 275 L = P2 *321L             The pressure of gas   = 212.4 torr

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