Chapter 6, Problem 6.54CU

Which of the following statements correctly completes the sentence: "The state postulate..." states that a system in equilibrium can be fully defined if two independent properties of the system are known. O O O O O ... relates the net heat and work inputs to a system to the change in its internal energy. allows calculation of change in entropy from the heat transfers in a system. states that the work done by a system to with a moving boundary is equal to the area under the process line when plotted on a pV diagram. allows us to convert extensive property values to intensive property values.

One-quarter Ibmol of oxygen gas (O₂) undergoes a process from p₁ = 20 lbf/in², T₁ = 500°R to p2 = 150 lbf/in². For the process W = -500 Btu and Q = -177.5 Btu. Assume the oxygen behaves as an ideal gas. Determine T2, in °R, and the change in entropy, in Btu/°R.

An ideal gas is confined to one side of a rigid, insulated container divided by a partition. The other side is initially 500 K, and V1 =0.2 m³. When the partition is removed, the gas expands to fill the entire container, which has a total volume of 0.5 m³. Assuming evacuated. The following data are known for the initial state of gas: P1 = 5 bar, T1 %3D that there is no change in the internal energy of the gas, determine the (a) pressure, in bar and the (b) product of mass, specific gas constant and T in the final state (in kPa-m³).