Thermodynamics Part 2 Flashcards
Enthalpy ‘H’ is defined as
H = E - PV
H = F - TS
H - E = PV
none of these
H - E = PV
One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
hour
day
minute
second
day
__________ functions are exemplified by heat and work.
Path
Point
State
none of these
Path
In an irreversible process
Tds = dE - dW = 0
dE - dW - Tds = 0
Tds - dE + dW< 0
Tds - dT + dW< 0
Tds - dE + dW< 0
What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope ?
3
2
1
0
1
The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
R loge 4
R log10 4
Cv log10 4
Cv loge 4
R loge 4
PVgamma = Constant (where, gamma = Cp/Cv) is valid for a/an __________ process.
isothermal
isentropic
isobaric
adiabatic
adiabatic
Claude gas liquefaction process employs cooling
at constant pressure.
by throttling.
by expansion in an engine.
none of these.
by expansion in an engine.
Which of the following will increase the volume of a real gas by four times ?
Doubling the absolute temperature as well as pressure of the gas.
Reducing pressure to one fourth at constant temperature.
Reducing temperature to one fourth at constant pressure.
Reducing the temperature to half and doubling the pressure.
Reducing pressure to one fourth at constant temperature.
Pick out the wrong statement.
A refriferation cycle violates the second law of thermadynamics.
Refrigeration cycle is normally represented by a temperature vs. entropy plot.
In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases.
One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW.
A refriferation cycle violates the second law of thermadynamics.
The equation, PV = nRT, is best obeyed by gases at
low pressure & high temperature.
high pressure & low temperature.
low pressure & low temperature.
none of these.
low pressure & high temperature.
Internal energy of an element at 1 atm and 25 C is __________ kcal/kg.mole.
0
273
25
none of these
0
Which of the following liquid metals has the highest thermal conductivity ?
Molten sodium
Molten lead
Mercury
Molten potassium
Molten sodium
Which of the following has the least thermal efficiency ?
Steam engine
Carnot engine
Diesel engine
Otto engine
Steam engine
Joule-Thomson Co-efficient at any point on the inversion curve is
infinity
+ ve
0
-ve
0
Pick out the wrong statement.
The values of (1) are zero for a real gas at its critical point.
Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process.
Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures.
During a reversible adiabatic process, the entropy of a substance remains constant.
Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures.
Number of components (C), phase (P) and degrees of freedom (F) are related by Gibbs phase rule as
P + F - C = 2
C = P - F + 2
F = C - P - 2
P = F - C - 2
P + F - C = 2
The value of Cp & Cv respectively for monoatomic gases in Kcal/kg Mole . K are
5 & 3
3.987 & 1.987
1.987 & 0.66
0.66 & 1.987
5 & 3
(aT/aP)H is the mathematical expression for (a = partial differential)
specific heat at constant pressure (Cp).
specific heat at constant volume (Cv).
Joule-Thompson co-efficient.
none of these.
Joule-Thompson co-efficient.
In case of a close thermodynamic system, there is __________ across the boundaries.
no heat and mass transfer
no mass transfer but heat transfer
mass and energy transfer
none of these
no mass transfer but heat transfer
During a reversible isothermal expansion of an ideal gas, the entropy change is
+ve
0
-ve
infinity
+ve
As the temperature is lowered towards the absolute zero, the value of (a(delta-F))/aT, then approaches
unity
zero
that of the heat of reaction
infinity
zero
Which of the following is not affected by temperature changes ?
Fugacity
Activity co-efficient
Free energy
None of these
None of these
For an ideal gas, the activity co-efficient is
directly proportional to pressure.
inversely proportional to pressure.
unity at all pressures.
none of these.
unity at all pressures.
ideal activity unity