Given that ΔH (fusion) of water is 6025 J/mol, Cp,m(ice) = 37.7 J K–1 mol–1, and Cp,m(water,liquid) = 75.3 J K–1 mol–1, calculate ΔG (in J) for the freezing of 89 moles of water at 1 atm pressure and the constant temperature T = 14.4 °C.

Question

I got -4458.92J, but it's wrong. Can anyone show me how to approach this question? Thank you!

Answer 1

ΔG = ΔH - TΔS

ΔH = 6025 J/mol
T = 14.4 °C = 287.6 K

ΔS = Cp,m(ice) - Cp,m(water,liquid)
= 37.7 J K–1 mol–1 - 75.3 J K–1 mol–1
= -37.6 J K–1 mol–1

ΔG = 6025 J/mol - (287.6 K)(-37.6 J K–1 mol–1)
= 6025 J/mol + 10862.56 J/mol
= 16887.56 J/mol

ΔG = (16887.56 J/mol)(89 mol)
= 1508982.04 J