Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU 19 - Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam.. Email: nguyentienthao@gmail.com 1 Chapter 16: Spontaneity, Entropy,
Trang 1Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU
19 - Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam Email: nguyentienthao@gmail.com 1
Chapter 16: Spontaneity, Entropy, and Free Energy (CHEM 2C)
16.1 Use the values of standard molar entropies in Appendix to calculate the entropy
change at 25°C and one atmosphere pressure for the reaction of hydrazine with hydrogen peroxide This explosive reaction has been used for rocket propulsion Do you think the reaction is spontaneous? The balanced equation for the reaction is
16.2 Using the Appendix, calculate the standard entropy of reaction of 1 mol of propane at
25oC:
C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(l)
16.3 At 298 K, the formation of ammonia bas a negative ǻ6osys:
16.4 Calculate ǻ6oat 25°C for the reaction :
CH 4 (g) + 2O 2 (g) - > CO 2 (g) + 2H 2 O(g)
given the standard entropy values:
16.5 Does the combustion of methane with oxygen occur spontaneously at 298K?
CH 4 (g) + 2O 2 (g) - > CO 2 (g) + 2H 2 O(g)
16.6 Mercury has an enthalpy of vaporization of 58.51 kJ/mol, and an entropy of
vaporization of 92.92 J/K mol What is the normal boiling point of mercury?
Hg(l) - > Hg(g)
16.7 &DOFXODWHǻ*orxnat 25oC for the following reactions:
give the values for the standard free energies of formation:
Trang 2Nguyen Tien Thao, Faculty of Chemistry, Hanoi College of Science, VNU
19 - Le Thanh Tong, Hoan Kiem, Hanoi, Vietnam Email: nguyentienthao@gmail.com 2
16.8 What is ǻ*ofor the autoionization of water at 25°C?
16.9 The oxidation of SO2: 2SO2(g) + O2(g) - > 2SO3(g)
is too slow at 298 K to be useful in the manufacture of sulfuric acid To overcome this low rate, the process is conducted at an elevated temperature
(b) In experments to determine the effect of temperature on reaction spontaneity, two
reach equilibrium at each temperature? (
c) Calculate ǻ*for the system in part (b) at each temperature
16.10 Diatomic nitrogen and oxygen molecules make up about 99% of all the molecules in
16.11 Make the same determination as in Problem 11.10, using heats of formation and
absolute entropies rather than free energies of formation
16.12 Use the thermodynamic data in Appendix to estimate the normal boiling point of
16.13 Mercury(II) sulfide is a dark red mineral called cinnabar Metallic mercury is
obtained by roasting the sulfide in a limited amount of air Estimate the temperature range
in which the standard reaction is product-favored using data in Appendix
16.14 Estimate the temperature range for which the following standard reaction is
product-favored
Additional problems:
Chapter 16: 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 81, 83, 85, 87
Complete at leat ….%, Deadline: …