Point of Interest Josiah Willard Gibbs

1 Verify by substitution that Equations 4.6 and 4.7 satisfy Equations 4.4 and 4.5. Then find the critical pressure for a van der Waals gas in terms of the constants a and b. 

2 Using the data in Table 2.2, calculate values for the critical volume and critical temperature of the following gases hydrogen, water, methane, and benzene. 

3 A liquid has a vapor pressure of 25.6 mm Hg at 25°C and a normal boiling point of 356°C. Calculate the heat of vaporization of this liquid. 

5 The volume change for a phase transition at some temperature can be obtained from the densities of each phase at the given temperature. (The volume is the number of moles divided by the molar density.) Given that the density of ice and liquid water at 273 K and 1 bar are, respectively, 0.915 and 1.000 g cm , find the molar volume change for melting at 273 K and Ibar. 

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