This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Homework 2 Answer (Due 01/28/2009 Wednesday) 1. (a) Calculate the molar volume, temperature, pressure of H 2 O at the critical point using van der Waals parameters a and b (see Table 1.1). (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. a) at critical point b 3 V C = 2 C 27b a P = 27Rb 8a T C = 1 1 C 09147 . 03049 . 3 3 V = = = Lmol Lmol b bar Lmol 6 . 220 ) 03049 . ( 27 barmol 5.537L 27b a P 2 1-2 2 2 C = = = K Lmol mol LbarK 16 . 647 03049 . 0831447 . 27 barmol 5.537L 8 27Rb 8a T 1 1 1-2 2 C = = = b) Density at critical point: mL g L mL / 197 . 1 1000 l 0.09147Lmo 18.0gmol D 1--1 = = 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 310 K. a) bar bar bar Lmol Lmol Lmol K V b V m m 773 . 92 384 . 157 . 93 ) 3 . ( barmol 0.0346L 0238 . 3 . 310 mol barK 0.083dm a RT P 2 1-2 2 1 1-1-1 3 2 He = = = = b) bar bar bar Lmol Lmol Lmol K V b V m m 948 . 33 522 . 61 470 . 95 ) 3 . ( barmol 5.537L 03049 . 3 . 310 mol barK 0.083dm a RT P 2 1-2 2 1 1-1-1 3 2 O H 2 = = = = 2 3. (From Atkins Ch1) The critical constants of methane are pc = 45.6 atm, Vc = 98.7 cm 3 mol-1 . (a) Calculate the van der Wa a ls parameters of the gas. (b) Calculate the critical temperature Tc. (c) Estimate the radius of the molecules....
View Full Document

{[ snackBarMessage ]}