Map The vapor pressure, P, of a certain liquid was measured at two temperatures

Question

Map The vapor pressure, P, of a certain liquid was measured at two temperatures If you were going to graphically determine the enthalpy of vaporizaton_aHap, for this liquid, what points would you plot? The data is shown in this table Number Number T (K)P (kPa) 225 575 To avoid rounding errors, use three significant figures in point 1: 004 1.17 3.23 6.34 e x values and fo significant figures in the y values Number Number NOTE: Keep the pressure units in kPa. point 2: 0.001 1.85 Determine the rise, run, and slope of the line formed by these points rise slope Number Number - 0027 00397 What is the enthalpy of vaporization of this liquid? Number J/mol

Explanation / Answer

We need to plot lnK on y axis and 1/T on x axis
P = 3.23
ln P = ln (3.23) = 1.17248
T = 225.0
1/T = 0.00444


point 1 is:
x = 0.00444
y = 1.17248


P = 6.34
ln P = ln (6.34) = 1.84688
T = 575.0
1/T = 0.00174


point 2 is:
x = 0.00174
y = 1.84688


----------------------------------------------------------------------------
rise = (y1-y2) = 1.17248 - 1.84688 = -0.6744
rise = (X1-X2) = 0.00444 - 0.00174 = 0.00271
slope = rise/run
= -0.6744/0.00271
= -249.2859
----------------------------------------------------------------------------
use
slope = - Hvap/R
= -249.2859 = -Hvap/8.314
Hvap = 2073 J/mol
Answer: 2073 J/mol

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