Question

In: Chemistry

The normal boiling point of ethanol, C2H5OH, is 78.3 °C, and its molar enthalpy of vaporization...

The normal boiling point of ethanol, C2H5OH, is 78.3 °C, and its molar enthalpy of vaporization is 38.56 kJ/mol. What is the change in entropy in the system when 68.3 g of C2H5OH(g)2at 1 atm condenses to liquid at the normal boiling point?

Solutions

Expert Solution

The normal boiling point of ethanol, C2H5OH, is 78.3 °C,

T   = 78.3 + 273   = 351.3K

The molar enthalpy of vaporization is 38.56 kJ/mol

Hvap   = 38.56 kJ/mol    = 38560J/mole

S    = Hvap /T

         = 38560J/mole/351.3K    = 109.76J/mole-K

no of moles of ethanol   = W/G.M.Wt

                                       = 68.3/46   = 1.485 moles

S      = 109.76J/mole-K * 1.485 moles

              = 163J/K    >>>>answer

The change in entropy in the system   = 163J/K    >>>>answer


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