A piston-cylinder device initially contains 0.15 kg of air initially at 2 MPa and 350℃. The air first expanded isothermally to 600 kPa, then compressed polytropically with a polytropic exponent of 1.1 to the initial pressure, and finally compressed at the constant pressure to the initial state. Determine the boundary work for each processand the net work of the cycle.

An insulated, vertical piston–cylinder device is purchased from a manufacturer. Upon purchase, it contains 3 kg of water at precisely 20 degrees celcius. The mass of the piston is such that it maintains a constant pressure of 300 kPa inside the cylinder. Liquid water at 2 MPA and 873.15 Kelvin is allowed to enter the cylinder from a supply line until the instant that the last drop of liquid in the cylinder vaporizes (saturated vapor). Find the mass of the steam that has entered [kg].

Question : Consider a piston-cylinder device containing m = 1 kg of air at the initial temperature T1 = 900K and pressure P1 = 895 kPa (state 1). The ambient temperature and pressure are maintained at T (e) = 300K and P (e) = 100 kPa. The air expands in a reversible adiabatic process until the air pressure reaches the ambient pressure P(e) (the intermediate state 2). Subsequently, the system undergoes an isobaric process until it reaches the dead state DS. Part ( A) Evaluate the volume and internal energy of the air in the initial state 1, in the intermediate state 2, and in the final dead state DS. Also evaluate the temperature of the air in the intermediate state

R-134a is a refrigerant, which is used inside of refrigerators and air conditioners. You can buy canisters of this as a compressed liquid, which can be used to recharge a leaky air conditioner. The canister initially contains 0.539 kg of R-134a at room temperature (25 °C). For simplicity, let's assume that the R-134a is initially saturated liquid. You use this canister to recharge an air conditioner, until the canister has half of its original mass remaining. The canister is upright with the exit on the top of the canister, so the exit flow is saturated vapor. In order to maintain the temperature at 25 °C, how much heat must be supplied to the canister? Note that this is why compressed liquid/gas canisters feel cold when you use them – they require heat - input to maintain constant T.