1. Last Time Where did all these equations come from?
Examples: ΔS, isentropic, isentropic efficiency, etc.

2. ΔS for Incompressible Substance
A 20 kg aluminum block initially at 200oC is brought into contact with a 20 kg block of iron at 100oC in an insulated enclosure. Determine the final equilibrium temperature and the amount of entropy generated during this process.

3. ΔS Ideal Gas and incompressible
A container filled with 45 kg of liquid water at 95oC is placed in a 90 m3 room that is initially at 12oC. Thermal equilibrium is established as a result of heat transfer between the water and air in the room. Using constant specific heat analysis, determine the final equilibrium temperature, the amount of heat transfer and the entropy generation.

4. Reversible, Steady Flow-Work
Liquid water enters a 25 kW pump at 100 kPa at 5 kg/s. Determine the highest pressure the liquid water can have at the exit of the pump. Neglect changes in kinetic and potential energy. Take the density of water to be 1000 kg/m3.

5. Isentropic Efficiency
An adiabatic compressor of a refrigeration system compresses saturated R-134a vapor at 0oC to 600 kPa and 50oC. What is the isentropic efficiency of this compressor.

6. Two Stage Compression
Air enters a two stage compressor at 100 kPa and 27oC and is compressed to 900 kPa. The pressure ratio across each stage is the same, and the air is cooled to the initial temperature between the two stages. Assuming the compression process to be isentropic, determine the power input to the compressor for a mass flow rate of 0.02 kg/s. What would your answer be if only one stage of compression were used?