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Clausius Clapeyron - Practice problems. Recap. Derived Clapeyron equation Defined possible assumptions Heat of vaporization, Δh vap , is constant with T AND P Change in volume is relatively constant with changes in T and P v α >>v β Vapor is an ideal gas
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Recap • Derived Clapeyron equation • Defined possible assumptions • Heat of vaporization, Δhvap, is constant with T AND P • Change in volume is relatively constant with changes in T and P • vα>>vβ • Vapor is an ideal gas • Helps us understand how P relates to T at equilibrium
Practice Problem #1 • What is the saturation pressure of a substance at 400 K when, at 1.0 bar, it boils at 330 K? • A=40 kJ/mol • B=0.01 kJ/molK
1. Start with ClapeyronEq • 2. State your assumptions • Make sure they are valid • Take 2 minutes to decide on assumptions and share
2. State Assumptions • Volume of state 1 >> Volume of state 2 • Ideal Gas • Heat of vap. is constant with T and P • Change in volume is constant with T and P
Practice Problem #2 • How much does the saturation pressure change for a fluid that obeys the following EOS if the temperature changes by 5 K?
1. Start with ClapeyronEq • 2. State your assumptions • Make sure they are valid • Take 2 minutes to decide on assumptions and share
2. State Assumptions • Volume of state 1 >> Volume of state 2 • Ideal Gas • Heat of vap. is constant with T and P • Change in volume is constant with T and P
Practice Problem #3 • Koretsky 6.18-What pressure is needed to ISOTHERMALLY compress ice initially at 268.15 K and 1.0 bar so that it changes phase?
1. Start with ClapeyronEq • 2. State your assumptions • Make sure they are valid • Take 2 minutes to decide on assumptions and share
2. State Assumptions • Volume of state 1 >> Volume of state 2 • Ideal Gas • Heat of melting is constant with T and P • Change in volume is constant with T and P
Practice Problem #4 • Koretsky 6.30-determine the second virial coefficient for a substance at T1. The saturation pressure is defined as
1. Start with ClapeyronEq • 2. State your assumptions • Make sure they are valid • Take 2 minutes to decide on assumptions and share
2. State Assumptions • Volume of state 1 >> Volume of state 2 • Ideal Gas • Heat of melting is constant with T and P • Change in volume is constant with T and P