Chapter 6, Problem 6.9P

Consider air in a piston than undergoes a polytropic process where PV^n= constant and n is a positive value. How do the pressure and volume change during expansion?

One kg of fluid is compressed reversibly according to a law PV=0.25, where p in bar and v in m'/kg. The final volume is one-fourth the initial volume. Calculate the work done on the fluid and sketch the process on the P-V diagram. (34 660 J)

1. An ideal gas undergoes a process for which the volume remains constant. At the start of the process, p = 15.625 psia, T¡ = 540 R, at the end p2 = 17.425 psia, T2 = 630 R. What is the work done (in Btu/ib) on the system? Your answer Submit

By choosing one of the three options given below, find the approximate temperature of the water in the closed container in the final state and show the state change in T-v, P-v diagrams.

1.5 kg of an ideal gas undergoes a process wherein the pressure decreases from 280 kPaa to 140 kPaa, while the volume increases from 0.045 cu.m to 0.135 cu.m. If the increase in internal energy for the process is 275 kJ and Cv =1.235 kJ/kg.K, find the change in enthalpy.

Q3. As shown in figure Q3, two tanks connected with valve are containing air with the given condition as shown in the figure. Now the valve is opened and the air in the two tanks are allowed to mix and reach to equilibrium condition with the surrounding temperature of 20°C. Considering the necessary assumptions, determine (a) the volume of tank B, (b) the pressure of both tanks after the valve is opened. (c) Can we use ideal gas low for saturated water steam at atmospheric pressure? Discuss the reason. (The gas constant of air is R = 0.287 kPa.m³/kg.K.) A В V = 1 m3 m = X m3 T= 17 °C T= 35 °C P = 450 kPa P = 300 kPa Figure Q3.

Example 2 A closed rigid container has a volume 1m³ and holds air at 345 kPa and 20 °C. Heat is added until the temperature is 327 °C. Determine the change in internal energy . R = 287 J / kg k Cv20 = 718 J /kg k, Cv327 = 768 J / kg .k %3D a/ using an average value of specific heat b/ considering the variation of specific heat with temperature. Take AU = m Au

Q2: (A) Hydrogen gas has a pressure of (60OKN/m2), volume of (0.03 m3) and a temperature of (40 C). Take R=D0.29 kJ/kg.k. Calculate:- (i) The amount mass of hydrogen (ii) The final temperature at constant volume and final pressure of (1.05 kN/m2)

1) A certain quantity of air is initially at 200 kPa (absolute) and 35°C. If the final state after a thermodynamic process is 120 kPa and 10°C, find the polytropic index of the process and describe what type of process this index represents.