Question

points RUTGERS /18219/assignments/272841 hapter 11 Tab Window Help Consider the plot of In Pvs 1/T for substance A. Calculate the value of the Molar Enthalpy of Vaporization from the plot. You must show all your work to get any credit.The value of Ris 8.314J/K.mol. (Hint: use the equal graph) X > Gyam R Rutgers Central.... Qo Any Search M Inbox Time Remaining Plot of In P vs 1/T for substance A 59:39 Post Inp IT: y"-2637.9x17.57 TE 00 8884 ? dI WAO % 5 6 on >Il Y * O U 9 H 0 C

Answer 1

ln(P) and 1/T are related as per the Clayperon equation. The equation is as follows:

$ln(P)=\frac{-\Delta H___{{vap}}}{ R}\times \frac{1}{T}+k$

where:

ΔH_vap - molar enthalpy of vapourization

R = 8.314 J/K.mol

k -a constant

This equation is in the form of a straight line with the following properties:

x-axis: (1/T)

y-axis: ln(P)

slope: (-ΔH_vap/R)

y-intercept - k

Therefore the value of ΔH_vap can be found from the equation of the straight line using the following equation:

ΔΗ, = = -slope x R vap

The equation of straight line from the graph is:

y = -2637.9x + 17.67

From the equation of line:

slope = -2637.9

Therefore the molar enthalpy of vaporization (ΔH_vap) is:

ΔΗ, = = -slope x R vap

$\dpi{120} {\Delta H___{{vap}}}=-(-2637.9)\times 8.314=21931.5 \: Joules$

Therefore the molar enthalpy of vaporization (ΔH_vap) is 21931.5 J or 21.93 kJ