It has been proposed that the phase transition enthalpy (DeltaHv) and entropy (D

Question

It has been proposed that the phase transition enthalpy (DeltaHv) and entropy (DeltaSV) for a lipid has a linear dependence on chain length (n), with a constant contribution from the end (DeltaH0 or DeltaS0): DeltaHV = nDeltaHinc + DeltaH0 DeltaSv = nDeltaSinc + Delta S0 where DeltaHincand DeltaSinc are the incremental contribution to enthalpy and entropy, spectively, from the increasing chain length. An empirical study has found the following values for disaturated phospholipids from n=14 to 22. 14 For DMPC, predict DeltaHV and DeltaSV from these empirical values. Compare to literature

Explanation / Answer

n value for DMPC =14

deHO= -7.1+0.3 or -7.1-0.3 , -6.8 or -7.4

dehinc= 0.93+0.02 or 0.93-0.02, 0.95 or 0.91

delSo= -12.2+1 or -12.1-1, -11.2 or -13.2

Dels inc =2.3+0.06 or 2.3-0.06 , 2.36 or 2.24

deHV = 14*0.95-6.8 =6.64 , 14* 0.91+ -7.4= 6.04 Cal/Jmole or 6.64*4.184 or 6.04*4.184 , 27.78 Joule or 25.27 Joules

literatre value is 26.6 to 20.2 joule/mole

DelSV= 14*2.36+-11.2=44.25 or 14* -2.24+ (-13.2) -44.56

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