[orgo814]

"When benzene freezes at 5.5 C its density changes from 0.879 g/cm^3 to 0.891 g/cm^3. It's enthalpy of fusion is 10.59 kJ/mol. Estimate the freezing point of benzene at 1000 ATM"

I get the whole problem. Using dP/dT = delta S/delta molar volume (assuming delta P/delta T). I can calculate delta S from the delta H and for delta P I'm just using a change of 1.0 ATM. My biggest problem is with the delta molar volume change. I'm finding the molar volumes by dividing the molar mass by the density but the book finds the change in molar volume by initial volume - final volume to get a positive value. If I did the normal way, final volume-initial volume the change would be negative resulting in a change of temperature that was negative but I don't understand why you would subject the final volume from the initial in this case. Any insight appreciated.

[rober2et]

Completely stuck on this problem too. Any help is a appreciated

[mjc123]

Quantities like enthalpy of fusion, volume change of fusion are defined as being for the process solid liquid. Thus enthalpies and entropies of fusion are both positive, volume change usually positive (but not for water). You should use these values to calculate the change in temperature of the transition, whether you think of it as melting or freezing.

If I did the normal way, final volume-initial volume the change would be negative resulting in a change of temperature that was negative

No it wouldn't. ΔV_freez would be negative, but so would ΔS_freez. You weren't thinking of using ΔV_freez with ΔS_fus, were you? Consistency!