If you were going to vaporizaton, tep, for this liquid, what points would you pl

Question

If you were going to vaporizaton, tep, for this liquid, what points would you plot? graphically determine the enthalpy of The vapor pressure, P, of a certain liquid was measured at two temperatures The data is shown in this table Number Number T (K)P (kPa) 275 3.94 625 5.89 To avoid rounding errors, use three significant figures in the x values and four significant figures in the y values. point 1 Number Number NOTE: Keep the pressure units in kPa. point 2 termine the rise, run, and slope of the line formed by these points rise run slope Number Number Number What is the enthalpy of vaporization of this liquid? Number J/mol

Explanation / Answer

we know that

the slope of the graph lnP vs 1/T can be used to obtain dHvap

so the x values will be 1/T and y values will be ln P

point 1 :

x = 1/275 = 0.00364

y = ln 3.94 = 1.371

point 2 :

x = 1/625 = 0.00160

y = ln 5.89 = 1.773

now

rise = y2 - y1 = 1.773 - 1.371 = 0.402

run = x2 - x1 = 0.0016 - 0.00364 = -0.00204

slope = rise / run = 0.402/ (-0.00204) = -197.0588

now

we know that

slope = -dHvap / R = -197.0588

dHvap = 197.0588 x R = 197.0588 x 8.314

dHvap = 1638.347 J /mol

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