Could someone help me on this one? Thanks

-- Anonymous, March 01, 2000

Answers

For A(l) 125C-75C

dS = n*Cp*ln(T2/T1) = (1mol)*(75 J/kmol)*ln(348/398)= -10.1J/K

For A(g) 155C-125C

dS = n*Cp*ln(T2/T1) = (1mol)*(29j/kmol)*ln(398K/428K)= -2.11J/K

dSvap= dS(l)+dS(g)+dStotal = 62.8J/k

for a phase change dSvap = dHvap/T

dHvap = dSvap*T=(62.8J/K)*(398K)=2.5*10^4J

-- Anonymous, March 01, 2000