• 1. Liquid octane enters an internal combustion engine operating at steady state with a mass flow rate of 1.8x 10^-3 kg/s and is mixed with the theoretical amount of air. The fuel and the air enter the engine at 25^oC and 1 atm. The mixture burns completely and combustion products leave the engine at 890 K. The engine develops a power output of 37 kW. Determine the rate of heat transfer from the engine, in kW, neglecting kinetic and potential energy effects. 

  2. A vessel of 2.0m³ capacity contains oxygen at 10 bar and C. The vessel is connected to another vessel of 4.0 m³ capacity containing carbon monoxide at 3 bar and C. A connecting valve is opened and the gases mix adiabatically. Calculate:

  (i) The final temperature and pressure of the mixture.

  (ii) The change of entropy of the system.

  Take: For oxygen Cv = 21.07 kJ/mole K, for carbon monoxide: Cv = 20.86 kJ/mole K

  
  

  
  

  
  

  Question five

  (a) A mixture of ideal gases consists of kg of nitrogen and kg of carbon dioxide at a pressure of bar and a temperature of C. Find :

  (i) The partial pressures of the mixture. (ii) The partial volumes of the mixture. (iii) the c_p and c_v of the
  mixture.

  (b) If the mixture in question five(a) is heated at constant volume to C, find the changes in internal energy, enthalpy, and entropy of the mixture.

  Take for CO₂ =1.286 and for N₂ = 1.4

  
  
  
  
  
  
  
  
  

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