Ethanol (C2H5OH) melts at -114 ∘C and boils at 78 ∘C. The enthalpy of fusion of ethanol is 5.02 kJ/mol, and it?
Ethanol (C2H5OH) melts at -114 ∘C and boils at 78 ∘C. The enthalpy of fusion of ethanol is 5.02 kJ/mol, and its enthalpy of vaporization is 38.56 kJ/mol. The specific heat of solid and liquid ethanol are 0.97 J/g⋅K are 2.3 J/g⋅K respectively.
1) How much heat is required to convert 37.0g of ethanol at 20∘C to the vapor phase at 78 ∘C?
2) How much heat is required to convert 37.0g of ethanol at -163∘C to the vapor phase at 78 ∘C?
I tired to find the q= mcdeltaT but would I leave the 37 grams or covert to moles of ethanol? would I find the pressures seperately according to temp then add together?
More Questions From This User See All
Answers & Comments
Verified answer
1. heat = mol x sp. ht x delta t = 37.0 g EtOH x (78 - 20)C x 2.3 J/gC = 4900 J
heat for vaporization = 38.58 kJ/mol x 37.0 g EtOH/46.0 g EtOH = 31.0 kJ
total heat required = 4.9 kJ + 31.0 kJ = 35.9 kJ
2. a. heat solid to mp = 37.0 g x .97 J/gC x ( -114C - (-163) = 1760 J
2.b heat to melt EtOh = 5.02 kJ/mol x 37.0 g EtOH/46 g EtOH = 4.04 kJ
2c. het to bring to bp = 37.0 G EtOH x 2.3 J/gC x (78 - (-114) = 16300 J
2d. vaporization energy from above 35900 J
total = 58,000 J (2.3 J/gC has 2 sig. figs)