During the phase change of a pure substance

1.	During the phase change of a pure substance
A.	dG = 0
B.	dP = 0
C.	dH = 0
D.	dU= 0
Answer» C. dH = 0

Discussion

No Comment Found

Related MCQs

If the pressure at station Q is 50 kPa, the change in entropy (sQ sp) in kJ/kgK is
Steam enters a well insulated turbine and expands isentropically throughout. At an intermediate pressure, 20 percent of the mass is extracted for process heating and the remaining steam expands isentropically to 9 kPa. Inlet to turbine: P = 14 MPa, T = 560 C, h = 3486 kJ/kg, s = 6.6 kJ/(kgK) Intermediate stage: h = 276 kJ/kg Exit of turbine: P = 9 kPa, hf = 174 kJ/kg, hg = 2574 kJ/kg, sf = 0.6 kJ/(kgK), sg = 8.1 kJ/(kgK) If the flow rate of steam entering the turbine is 100 kg/s, then the work output (in MW) is____.
A gas is heat ed in a duct as it flows over a resistance heater. Consider a 101 kW electric heat ing syst em. The gas ent ers the heat ing section of the duct at 100 kPa and 27 C with a volume flow rate of 15 m /s. If heat is lost from the gas in the duct to the surroundings at a rate of 51 kW, the exit temperature of the gas is (Assume constant pressure, ideal gas, negligible change in kinetic and potential energies and constant specific heat: Cp = 1 kJ/kg. K; R = 0.5 kJ/kg K).
In order to burn 1 kilogram of CH4 completely, the minimum number of kilograms of oxygen needed is (take atomic weights of H, C and O as 1, 12 and 16 respectively)
One kg of air (R = 287 J/kgK) undergoes an irreversible process between equilibrium state 1 (20 C, 0.9 m3) and equilibrium state 2 (20 C, 0.6 m3). The change in entropy s2 s1 (in J/ kgK) is ______.
An ideal gas of mass m and temperature T1 undergoes a reversible isothermal process from an initial pressure P1 to final pressure P2. The heat loss during the process is Q. The entropy change S of the gas is
One kg of an ideal gas (gas constant R = 287 J/ kgK) undergoes an irreversible process from state-1 (1 bar, 300 K) to state-2 (2 bar, 300 K). The change in specific entropy (s2 s1) of the gas (in J/kgK) in the process is _______.
An ideal gas undergoes a process from state 1 (T1 = 300 K, p1 = 100 kPa) to state 2 (T2 = 600 K, p2 = 500 kPa). The specific heats of the ideal gas are: cp = 1 kJ/kg-K and cv = 0.7 kJ/kg-K. The change in specific entropy of the ideal gas from state 1 to state 2 (in kJ/kg-K) is _________ (correct to two decimal places)
One kg of an ideal gas (gas constant, R= 400 J/ kgK; specific heat at constant volume, cp = 1000 J/kgK) at 1 bar, and 300 K is contained in a sealed rigid cylinder. During an adiabatic process, 100 kJ of work is done on the system by a stirrer. The increase in entropy of the system is _______ J/K.
A turbocharged four-stroke direct injection diesel engine has a displacement volume of 0.0259 m3 (25.9 liters). The engine has an output of 950 kW at 2200 rpm. The mean effective pressure (in MPa) is closest to

During the phase change of a pure substance

Discussion

No Comment Found

Related MCQs

Reply to Comment