promotion image of download ymail app
Promoted
amy asked in Science & MathematicsChemistry · 2 months ago

How much energy in kilojoules is released when 25.2 g of ethanol vapor at 88.0 ∘C is cooled to -14.0 ∘C ?

Ethanol has mp=−114.1∘C, bp=78.3∘C, ΔHvap=38.56kJ/mol, and ΔHfusion=4.93kJ/mol. The molar heat capacity is 112.3 J/(K⋅mol) for the liquid and 65.6 J/(K⋅mol) for the vapor.

1 Answer

Relevance
  • 2 months ago

    (25.2 g C2H5OH) / (46.0684 g C2H5OH/mol) = 0.547013 mol C2H5OH

    (65.6 J/(K⋅mol)) x (88.0 - 78.3)K x (0.547013 mol) =

    348.075 J = 0.348075 kJ from cooling the vapor to its boiling point

    (38.56 kJ/mol) x (0.547013 mol) = 21.092821 kJ from condensing the vapor

    (112.3 J/(K⋅mol)) x (78.3 - (-14.0))K x (0.547013 mol) = 5669.948 J =

    5.669948 kJ from cooling the condensed vapor to -14.0°C

    0.348075 kJ + 21.092821 kJ + 5.669948 kJ = 27.1 kJ total

    • Commenter avatarLogin to reply the answers
Still have questions? Get your answers by asking now.