The first law of thermodynamics is a statement of conservation of
Heat
Momentum
Energy
Work
Correct Answer :
C. Energy
Related Questions
During the phase transition, __________ changes.
Pressure
Volume
Temperature
All (A), (B) and (C)
In the equation, PVn = Constant, if the value of n = 0, then it represents a reversible __________ process.
Isobaric
Isothermal
Isentropic
Isometric
In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v1 = 1 m3 and v23 m3) is maximum, when the value of 'n' is
0
1
y = 1.44
1.66
In jet refrigerators, the refrigerating fluid is practically always
Water
Ammonia
Freon
Brine
Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.
Reaction mechanism
Calculation of rates
Energy transformation from one form to another
None of these
In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be
5.2
6.2
0.168
Data insufficient, can't be found out
All gases during throttling process at atmospheric temperature and pressure show a cooling effect except
CO2
H2
O2
N2
An irreversible process
Is the analog of linear frictionless motion in machines
Is an idealised visualisation of behaviour of a system
Yields the maximum amount of work
Yields an amount of work less than that of a reversible process
For a spontaneous process, free energy
Is zero
Increases
Decreases whereas the entropy increases
And entropy both decrease
The value of Cp & Cv respectively for monatomic gases in Kcal/kg Mole.°K are
5 & 3
3.987 & 1.987
1.987 & 0.66
0.66 & 1.987
The Joule-Thomson co-efficient is defined as (∂T/∂P)H. Its value at the inversion point is
∞
1
0
-ve
The intensive properties are
Molar volume, density, viscosity and boiling point
Refractive index and surface tension
Both (A) and (B)
None of these
For an exothermic reaction
Only enthalpy change (ΔH) is negative
Only internal energy change (ΔE) is negative
Both ΔH and ΔE are negative
Enthalpy change is zero
A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
Minimum
Zero
Maximum
None of these
A solid is transformed into vapour without going to the liquid phase at
Triple point
Boiling point
Below triple point
Always
Gibbs-Duhem equation
States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Applies only to binary systems
Finds no application in gas-liquid equilibria involved in distillation
None of these
For the reversible exothermic reaction, N2 + 3H2 2NH3, increase of pressure would
Shift the equilibrium towards right
Give higher yield of NH3
Both (B) and (C)
Neither (A) nor (B)
What is the degree of freedom for a system comprising liquid water equilibrium with its vapour?
0
1
2
3
In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
Enhanced COP
Decreased COP
No change in the value of COP
Increased or decreased COP; depending upon the type of refrigerant
Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of
Solution
Vaporisation
Formation
Sublimation
Joule-Thomson co-efficient depends on the
Pressure
Temperature
Both (A) & (B)
Neither (A) nor (B)
For a reversible process involving only pressure-volume work
(dF)T, p < 0
(dF)T, p > 0
(dF)T, p = 0
(dA)T, v < 0
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
2.73
28.3
273
283
A solute distributes itself between two nonmiscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount. This is
The distribution law
Followed from Margules equation
A corollary of Henry's law
None of these
Gibbs free energy at constant pressure and temperature under equilibrium conditions is
∞
0
Maximum
Minimum
The most important application of distribution law is in
Evaporation
Liquid extraction
Drying
Distillation
Sublimation temperature of dry ice (solid CO2) is __________ °C.
-273
0
-78
5
A reasonably general expression for vapourliquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yi is the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of
Temperature only
Temperature and pressure only
Temperature, pressure and liquid composition xi only
Temperature, pressure, liquid composition xi and vapour composition yi
The activity of an ideal gas is numerically __________ its pressure.
More than
Less than
Equal to
Data insufficient, can't be predicted
Which of the following units is not present in both the vapor compression refrigeration system and absorption refrigeration system?
Expansion valve
Condenser
Refrigerator
Compressor