Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is
Superheated vapour
Partially condensed vapour with quality of 0.9
Saturated vapour
Partially condensed vapour with quality of 0.1
Correct Answer :
A. Superheated vapour
Related Questions
What happens in a reversible adiabatic expansion process?
Heating takes place
Cooling takes place
Pressure is constant
Temperature is constant
Work done is a
Property of the system
Path function
Point function
State description of a system
1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be
35 K
174 K
274 K
154 K
Water on heating from 1 to 4°C
Contracts
Expands
Has same volume
May contract or expand
Which of the following is not an intensive property?
Volume
Density
Temperature
Pressure
At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be
More
Less
Same
More or less; depending on the system
Which of the following is not an extensive property?
Free energy
Entropy
Refractive index
None of these
Pick out the wrong statement:
The expansion of a gas in vacuum is an irreversible process
An isometric process is a constant pressure process
Entropy change for a reversible adiabatic process is zero
Free energy change for a spontaneous process is negative
The value of gas constant 'R' is
1.987 cal/gm mole °K
1.987 BTU/lb. mole °R
Both (A) and (B)
Neither (A) nor (B)
Which of the following exemplifies an adiabatic process?
Melting of ice
Condensation of alcohol vapor
Sudden bursting of a cycle tube
Evaporation of water
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
0
1
2
3
The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and noctane into pure compounds each at 1 atm is
-2 RT ln 0.5
-RT ln 0.5
0.5 RT
2 RT
In an ideal refrigeration cycle, the change in internal energy of the fluid is
+ve
-ve
0
Either of the above three; depends on the nature of refrigerant
Heat is added at constant temperature in an ideal __________ cycle.
Stirling
Brayton
Rankine
None of these
With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure
Increases
Decreases
Remain same
Decreases linearly
In Joule-Thomson porous plug experiment, the
Enthalpy does not remain constant
Entire apparatus is exposed to surroundings
Temperature remains constant
None of these
Refrigerants commonly used for domestic refrigerators are
Ethyl chloride or methyl chloride
Freon-12
Propane
NH3 or CO2
In jet refrigerators, the refrigerating fluid is practically always
Water
Ammonia
Freon
Brine
When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change. This is called the
Le-Chatelier principle
Kopp's rule
Law of corresponding state
Arrhenius hypothesis
(∂T/∂P)H is the mathematical expression for
Specific heat at constant pressure (Cp)
Specific heat at constant volume (Cv)
Joule-Thompson co-efficient
None of these
In case of an __________ process, the temperature of the system increases.
Isothermal compression
Isothermal expansion
Adiabatic expansion
Adiabatic compression
Number of phases in a colloidal system is:
1
2
3
4
Compound having large heat of formation is
More stable
Less stable
Not at all stable (like nascent O2)
Either more or less stable; depends on the compound
What is the ratio of adiabatic compressibility to isothermal compressibility?
1
< 1
> 1
>> 1
Which is not constant for an ideal gas?
(∂P/∂V)T
(∂V/∂T)P
(∂P/∂V)V
All (A), (B) & (C)
Pick out the correct equation relating 'F' and 'A'.
F = A + PV
F = E + A
F = A - TS
F = A + TS
The enthalpy change when ammonia gas is dissolved in water is called the heat of
Solution
Formation
Dilution
Combustion
In a reversible process
Tds = dE + dW
dE - dW = Tds
dW - dE = Tds
Tds - dW + dE >0
Normal temperature and pressure (N.T.P.) corresponds to
0°C and 760 mm Hg
15°C and 760 mm Hg
20°C and 760 mm Hg
0°C and 1 kgf/cm2
The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are:
1
2
3
0