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Situational Problem (11-13) A 1 kg of air at 250 kPa pressure and

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Situational Problem (11-13) A 1 kg of air at 250 kPa pressure and...

 

Situational Problem (11-13)

A 1 kg of air at 250 kPa pressure and 100 ?C were to be expanded at constant pressure in a closed process to twice the original volume.

11.      Determine the final state of air.

a. 746                                    b. 673                                   c. 473                                   d. 546

 

12.      Determine the amount of heat.

a. 93.8                                   b. 375.3                                c. 750.6                                d. 562.9

 

13.      Determine the work involved in the process.

a. 428.2                                b. 214.1                c. 107.05                              d. 53.53

 

Situational Problem (14-15)

A closed gaseous system undergoes a reversible process in which 153 kJ of heat are rejected and the volume changes from 0.55 m³ to 0.14 m³. The pressure is constant at 150 kPa.

14.      Determine the work done.

a. - 41.5               b. - 71.5               c. - 51.5                                d. - 61.5

 

15.      Determine the change in internal energy of the system.

a. 71.5                                   b. 91.5                                  c. 81.5                                   d. 61.5

 

16.      Steam is the working substance of a piston-cylinder assembly which initially has a specific volume of 0.09596 m³/kg at 1.8 MPa undergoes a constant pressure until its final specific volume is 0.13796 m³/kg. Determine the work done.

a. 80.5 kJ/kg                       b. 90.7 kJ/kg                       c. 85.4 kJ/kg                       d.75.6 kJ/kg

 

Situational Problem (17-20)

A 1.5 kg quantity of ethane ( k = 1.187 ) is cooled at constant pressure from 170 ?C to 65 ?C.

17.      Determine the change of enthalpy.

a. 276.4                               b. 254.6                c. 232.8                                d. 218.2

 

18.      Determine the change of internal energy.

a. 218.2                                b. 276.8                c. 232.8                                d. 254.6

 

19.      Determine the heat transferred.

a. 254.6                                b. 276.4                                c. 218.2                                d. 232.8

 

20.      Determine the work.

a. 86.3                                   b. 69.3                                  c. 26.6                                   d. 43.6