2.9.Approximately 1070 drops of the mass are required to
raise the temperature by 1.00°C.
2.13.Equation 2.10 is applicable to isolated systems (no trans-
fer of matter or energy). Equation 2.11 is applicable to closed
systems, which allow a transfer of energy between system and
surroundings.
2.14. U70.7 J
2.15.w5180 J
2.16.w5705 J (reversible), w912 J (irreversible).
More work is obtained from the reversible expansion.
2.20. (a)wtot 0 (b) U 0
2.21. (a)pfinal242 atm (b)w0, q1.44 106 J,
U1.44 106 J
2.22.When qw, U0 even if final conditions aren’t
the same as initial conditions.
2.23.w2690 J, q1270 J, U1420 J, H
1420 J
2.24. H2260 J, w172 J, U2088 J
2.26. U4450 J, pfinal714 atm
2.27.The units should be J/K, J/K^2 , and JK, respectively.
2.33.T(He) 36K (compared to 40 K measured experimen-
tally), T(H 2 ) 224 K (compared to 202 K measured experi-
mentally).
2.39.Process is adiabatic: w107 J, U107 J
2.40.Tf186°C
2.44.The temperature decreases to about 55.0% of its orig-
inal temperature.
2.45. H333.5 J, U333.491 J 333.5 J (4 sig figs).
Even in the case of H 2 O, which experiences a 9% change in
volume upon melting, the difference between Hand Uis
negligible for the solid-liquid phase change.
2.46.The system does 0.165 J of work.
2.48.6.777 g of ice can be melted.
2.55.q31723 J, U31723 J, w0, H31735 J
2.56.q31723 J, H31723 J, w0, U31711 J
2.57. H(492.9 KJ) 285.94 kJ, not much different than
H(25°C).
Chapter 3
3.1. (a)spontaneous (b)not spontaneous (c)spontaneous
(d)not spontaneous (e)spontaneous (f)spontaneous (g)
not spontaneous
3.3.e0.267
3.4.The individual steps must also be carried out under the
proper conditions (i.e., reversible & adiabatic, or reversible &
isothermal). If they are, then according to the data, e0.303.
3.5.Tlow36°C
3.6.e0.268
3.12. S74.5 J/K
3.14. S23.5 J/K
3.15. S100.9 J/K
3.16.Greater than 0.368 J/K
3.18. Sequals zero if the process is reversible. However, in
most cases, release of compressed gas is irreversible, so the
change in entropy should be greater than zero.
3.22. Smix4.6 J/K
3.23. Smix2.20 J/K, Sexpansion3.72 J/K; Stotal5.92
J/K.
3.34.From lowest to highest entropy: Cdia Cgra Si
Fe NaCl BaSO 4
3.36. (a)163.29 J/K (b)44.24 J/K (c)1074.1 J/K
3.39.The difference between the two values of entropy
change is 118.87 J/K. The difference is due to the phase of the
product, H 2 O.
3.40. S37.5 J/K
3.41. S9.09 105 J/KChapter 4
4.8.Since Ais less than or equal to the maximum amount
of work the system can do, calculate work for the given con-
ditions and recognize that Amust be less than that, since the
process is not reversible: A 517 J.
4.9.The reaction can do up to 237.17 kJ per mole of H 2 O re-
acted.
4.10. A536 J
4.11.w15,700 J, q15,700 J, U0, H0, A
15,700 J, S57.5 J/K
4.12.97.7 kJ
4.13.2.3 kJ and 138.3 kJ
4.17. A0 (because it’s a state function)
4.23. (a)yes (b)yes (c)yes (d)yes (e)no
4.28. Ushould change by approximately 4460 J.
4.34.38.5 J/K
4.36.slope H
4.37. G967 J
4.42.All are intensive variables.
4.44. (a)1.91 103 J (b)5.74 103 J
4.45.29.7 JChapter 5
5.5.The minimum is 0. The maximum is 0.169 mol, as
determined by the limiting reagent HCl.Chapter 5 807