Total Marks 25
Question 1 (a): A system receives 5 kJ of heat transfer and experiences a decrease in energy in the amount of 5 kJ. Determine the amount of work done by the system. 3
Question 1 (b): Define latent heat? 2
Question 2: True/ False 5
- A heat engine is a thermodynamic system operating in a thermodynamic cycle to which net heat is transferred and from which net work is delivered.
- The thermal efficiency is always less than 2 or less than 200 percent.
- Internal energy, kinetic and potential energies are intensive properties, because they depend on the mass of the system.
- A pure substance has the different chemical composition throughout.
- In a steady flow process a fluid flow through a control volume steadily.
Question 3 (a): Air flows into an open system and carries energy at the rate of 300 kW. As the air flows through the system it receives 600 kW of work and loses 100 kW of energy by heat transfer to the surroundings. If the system experiences no energy change as the air flows through it, how much energy does the air carry as it leaves the system, in kW? 3
Question 3 (b): Define the state postulate for a simple pure substance? 2
Question 4(a): Calculate the change of enthalpy as 1 kg of oxygen is heated from 300 to 1500 K. Assume ideal-gas behavior. 3 Question 4(b): What is superheated vapor according to state postulate? 2
Question 5: Determine the enthalpy of 1.5kg of water contained in a volume of 1.2m3 at 200kPa.5