090119_Homework2 - 6. Calculate the following values for He...

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Chem340 Physical Chemistry for Biochemists Dr. Yoshitaka Ishii Homework 2 Due Date Jan 28, 2009 1. (a) Calculate the molar volume, temperature, and pressure of H 2 O at the critical point using van der Waals parameters a and b (see Table 1.1 below). (b) Obtain the density of H 2 O at the critical point, and compare it with that of liquid H 2 O (~1 g/mL). Assume that the molar mass of H 2 O is 18.0. 2. Calculate the pressures for (a) He and (b) H 2 O from van der Waals equation when the molar volume is 0.3 L and T = 310 K. 3. The critical constants of methane are Pc = 45.6 atm, Vmc = 98.7 cm 3 mol -1 . (a) Calculate the van der Waals parameters of the gas. (b) Calculate the critical temperature Tc. (c) Estimate the radius of the molecule. 4. Can you use the van der Waales equation below the critical temperature of the gas? If so what kind of caution or modification is needed? 5. Calculate the average translational energy of (a) one Ar molecule and (b) one mole of Ar assuming that it is an ideal gas.
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Unformatted text preview: 6. Calculate the following values for He and O 2 . (a) the average speed <C>, (b) The root-mean-squared average of the speed. Crms = <C 2 > 1/2 , (c) most probable C, C mp in Maxwell-Bolzmann distribution. Assume that T = 300K for all the case. 7. Prove that = > < 3 2 2 3 2 2 4 dC C kT mC kT m C exp / gives 2 1 8 / = > < M RT C , where C denotes the speed of a gas molecule B that has a mass m and M is a molar mass of B. 8. Plot a Maxwell-Boltzmann distribution P(C) = 2 2 2 3 2 2 4 C RT MC RT M C = > < exp / using Excel or other software for N 2 at 200K and 400K in 0 C < 1500 m/s. 9. How much of the average translational energy E trans and rotational energy E rot do you expect for one mole of (a) Ar, (b) H-Cl, (c) C 2 H 2 , (d) NH 3 , (e) C 6 H 6...
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This note was uploaded on 04/14/2010 for the course CHEM 340 taught by Professor Yoshitakaishii during the Spring '07 term at University of Illinois, Urbana Champaign.

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