CHEM 4010                                                                                                  Spring, 2008

  

 

Use the following data to calculate the standard entropy of gaseous ammonia at 298.15 K:  Dfus H = 5.655 kJ mol-1 at the melting point of 195.42 K , and Dvap H = 23.351. kJ mol- 1 at the boiling point of 239.74 K. Assume that the heat capacity of the liquid has a constant value of 74.85 J K-1 mol-1, and that the heat capacity of the gas is constant at 35.52 J K-1 mol-1.  The heat capacity of solid ammonia is given as a function of temperature below.  Compare your result with the value given in Table 2.7 of the Textbook.

 

 

 

T/ K 

 

Cp,m/ J K-1 mol-1

15

0.7322

20

1.539712

30

4.322072

40

7.702744

50

11.14199

60

14.53522

70

17.70669

80

20.72754

90

23.48061

100

26.13326

110

28.77337

120

31.36745

130

33.97408

140

36.39662

150

38.79405

160

41.19566

170

43.59728

180

46.14952

190

48.99464

195.42

50.12432