SPH203,293 CEP CAT 2 August2023

SPH 203/293 Thermal dynamics I

CAT 11

5th August 2023


  • Take R=8.31 JK-1mol-1
  • Email scanned answer sheets in pdf format to phycats@gmail.com
  • Submission deadline: 12th August 2023
  • Note that late submissions will be penalised.

a) A quantity of 0.2 mol of air enters a diesel engine at a pressure of 1.04x105 Pa and at a temperature of 297 K. Assuming that air behaves like an ideal gas, find the volume of this quantity of air. (4 marks)

b) The air is then compressed to one twentieth of this volume, the pressure having risen t0 6.89x10Pa, Find the new temperature. (4 marks)

c) Heating of the air then takes place by burning a small quantity of fuel in it to supply 6150 J. This is done at a constant pressure of 6.89x10Pa as the volume of air increases and the temperature rises to 2040 K. Find:

               (i) the molar heat capacity of air at the constant pressure (3 mark)

               (ii) the volume of the air after burning the fuel (3 marks)

               (iii) the work done by the air during this expansion (3 marks)

               (iv) the change in internal energy of the air during this expansion (3 marks)

Dr. Margaret W. Chege

1 Comment(s)

Paul Mutisya Mutua (Tue, 19th Dec 2023, 2:58 PM)
Good afternoon Dr. I'm kindly writing to enquire some of the areas of research that you can be able to supervise a student at MSc. Environmental physics. I would wish to have you as my supervisor if you won't mind.

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