Page 144 - Bruno Linder Elementary Physical Chemistry

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

Appendix A: Homework Problem Sets 129

11. The standard enthalpy of combustion of l-butene (C 4 H 8 ,g) is
−2710 kJ mol −1 and the standard enthalpy of vaporization of liquid
l-butene is 18 kJ mol −1 . Calculate the standard enthalpy and the
standard energy of combustion of liquid l-butene.

ProblemSet III.Chapters 3,4,5
1. 250 kg of Al is cooled from 298.15K to 200 K at constant pressure.
The molar heat capacity of Al is 24.4JK −1 mol −1 . Calculate the heat
emitted and the change in entropy.
2. 20 L of CO 2 at 275 K and 1 atmosphere pressure is compressed to a
volume V f . The change in entropy is −12.0JK −1 .Calculate V f .
3. The enthalpy of vaporization of a substance is 30 kJ mol −1 at the normal
boiling point T b = 350 K. What is the entropy of vaporization of the
substance, and what is the entropy change of the surroundings?
4. Calculate the standard reaction enthalpies for
(a) Hg(l) + Cl 2 (g) → HgCl (s)
2
(b) Zn(s) + Cu 2+ (aq) → Zn 2+ +Cu(s)
5. The enthalpy of combustion of C 6 H 5 OH(s) at 298 K is −3055 kJ mol −1 .
The standard entropy of this compound at 298 K is 146 JK −1 mol −1 .
Calculate the

(a) enthalpy of formation of C 6H 5 OH(s)
(b) entropy of formation of C 6H 5OH(s)
(c) Gibbs free energy of formation of C 6 H 5 OH(s)
(d) Gibbs free energy of the combustion reaction
(e) the non-PV work, w other

6. Assuming that at 2000 K and 100 kbar the transition reaction
C (graphite) C (diamond)

is reversible (in equilibrium), calculate the ∆S for this reaction. The
o
standard enthalpy change at this temperature and pressure is ∆H reac =
−1
1.91 kJ mol .
7. The standard Gibbs free energy of transformation of trans-2-pentane
to cis-2-pentane at 127 Cis∆G o =3.7kJmol −1 . Calculate the
◦
equilibrium constant for the isomerization of cis-2-pentane to trans-
2-pentane.