Lesson 35



Name:ETP Section:t3 Start Time:23:45:57 Instructor:pattersonet Course:421



1. The van der Waals equation of state can be expressed by:


Physically, what does each of the "correction terms" represent? Why is the "a" term positive but the "b" term negative? Why does the "a" term have a V-2 dependence?

Enter your answer here:



2. Suppose you look at a P versus T coexistence curve for liquid water and steam and read two points off the curve: (P = 1.018 atm at T = 373.6 K) and (P = 0.982 atm at T = 372.6 K).

What is the sign of dP/dT? Explain why this makes sense physically.

Use the information given to estimate the Latent Heat of Vaporization of water. How does your estimate compare to the accepted value for water of 540 cal/g, or 4.07 x 104 J/mole? (The gas constant R is 8.314 J/mole K.) Please briefly explain your steps.

Enter your answer here:



3. The triple point of a substance is the point in the (P, T) plane

Check the correct answer:
a) which is three times harder to find than the critical point.
b) which has a temperature equal to the melting point temperature.
c) at which the pressure is one third the critical point pressure.
d) at which all three phases of the substance coexist.

Below is a space for your thoughts, including general comments about today's assignment (what seemed impossible, what reading didn't make sense, what we should spend class time on, what was "cool", etc.):


You may change your mind as often as you wish. When you are satisfied with your responses click the SUBMIT button.

I received no help from anyone on this assignment.
I received help from someone on this assignment (document in comments section).