Page 143 - Bruno Linder Elementary Physical Chemistry

August 18, 2010 11:37 9in x 6in b985-appA Elementary Physical Chemistry

128 Elementary Physical Chemistry

9. Develop the van der Waals equation of state in virial form and obtain
explicit expressions for the virial coefficients B and C in terms of the
van der Waals parameters a and b. [Note: The expansion of 1/(1 − x) ≈
2
1+ x + x + ··· ]

Problem Set II. Chapter 2
1. How much work is required to raise an object weighing 25 kg to a
height of 5 m on the surface of the earth? (The gravitational constant
is 9.81 ms −2 .)
2. 5 moles of a gas is expanded isothermally and reversibly at 298.5 K
3
3
from 100 cm to 300 cm . Calculate the work.
3. The heat of fusion of Na is 27.4 cal/g at 370.95K. How many kilojoules
of heat are required to melt 250 kg of Na?
3
4. A room of volume 110 m contains a gas (air), whose molar heat
capacity at constant pressure is C p,m =21.0JK −1 .If the room is
heated from 300K to 310K (at constant volume), calculate the heat
required to accomplish this. The molar volume of the gas at T = 300 K
is 25 L mol −1 .
5. One mol of O 2 is heated at constant pressure from 250 K to 275 K. The
1
molar heat capacity at constant pressure is C p,m =29.4JK mol −1 .
Calculate C V,m,q P ,q V , ∆H, ∆U.
6. The standard enthalpy of formation of CH 3C 6 H 5 (methyl benzene)
−1
is +50.0kJmol . What is the standard enthalpy of combustion?
(The standard enthalpies of formation of CO 2 (g) and of H 2O(l) are
respectively −393.51kJ mol −1 and −285.83kJ mol −1 .)
7. The standard enthalpy of combustion of C 8H 18 (l) (octane) is
−546.1kJ mol −1 . What is the standard enthalpy of formation?
8. The standard enthalpy of formation of AgCl(s) is −127.1kJ mol −1 .
+
The standard enthalpy of formation of Ag (aq) is 105.6kJ mol −1 and
−
of Cl (aq) it is −167.2kJ mol −1 . Calculate the standard enthalpy of
solution of AgCl in H 2O.
9. The enthalpy of combustion of diamond is −395.4kJ mol −1 and of
graphite is −393.5kJ mol −1 . Calculate the enthalpy of conversion of
graphite into diamond.
−1
10. 1.6 g of glucose (M = 180.2g mol .) burns in air (combines with
oxygen) at constant pressure and temperature. The standard enthalpy
of combustion of sucrose is −2808kJ mol −1 . How much heat is released?