I'm not sure how to calculate delta Hvap from the title equation: ln P= (-delta Hvap/R)*(1/T) + C and the linear regression equation I've gotten from my data: y = -3653.4x + 14.442. That equation comes from a graph of Ln Pvap Versus 1/Temperature, Temp. being in Kelvin.

Any help would be much appreciated!

If it's any help, here are the data (sorry it's so clumped, I can't get it to look any nicer here):

Initial Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

P total (kPa) n/a 105.4 105.95 108.43 114.12 118.33

P air (kPa) 98.81 98.58 98.87 99.98 102.12 103.43

P vap (kPa) n/a 6.82 7.08 8.45 12.00 14.9

Temperature (K) 295.4 294.7 295.58 298.9 305.3 309.21

Ln P vap (kPa) n/a 1.919859472 1.957273908 2.134166441 2.48490665 2.701361213

1/Temperature (K) n/a 0.0034 0.0034 0.0034 0.0033 0.0032