If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is __________ law.
Hess's
Kirchoff's
Lavoisier and Laplace
None of these
Correct Answer :
A. Hess's
Related Questions
For an irreversible process involving only pressure-volume work
(dF)T, p <0
(dF)T, p = 0
(dF)T, p > 0
(dA)T, v >0
Mollier diagram is a plot of
Temperature vs. enthalpy
Temperature vs. enthalpy
Entropy vs. enthalpy
Temperature vs. internal energy
The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
Temperature
Pressure
Composition
All (A), (B) and (C)
Internal energy change of a system over one complete cycle in a cyclic process is
Zero
+ve
-ve
Dependent on the path
If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
100
50
205
200
Number of degrees of freedom for a three phase system in equilibrium comprising of three nonreacting chemical species is
2
0
1
3
For an isothermal reversible compression of an ideal gas
Only ΔE = 0
Only ΔH =0
ΔE = ΔH = 0
dQ = dE
First law of thermodynamics deals with the
Direction of energy transfer
Reversible processes only
Irreversible processes only
None of these
Specific/molar Gibbs free energy for a pure substance does not change during
Sublimation
Vaporisation
Melting
Either (A), (B) or (C)
Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation.
Gibbs-Duhem
Maxwell's
Clapeyron
None of these
In a working refrigerator, the value of COP is always
0
< 0
< 1
> 1
Which is not a refrigerant?
SO2
NH3
CCl2F2
C2H4Cl2
Refrigeration cycle
Violates second law of thermodynamics
Involves transfer of heat from low temperature to high temperature
Both (A) and (B)
Neither (A) nor (B)
For a cyclic process, a fixed ratio between heat and work
Always exists
May exist
Never exists
Is difficult to predict
The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
Kinematic viscosity
Work
Temperature
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
With increase in temperature, the internal energy of a substance
Increases
Decreases
Remains unchanged
May increase or decrease; depends on the substance
Compressibility factor for almost all the gases are approximately same at the same
Pressure and temperature
Reduced pressure and reduced temperature
Critical pressure and critical temperature
None of these
In the reaction, represented by, 2SO2 + O2 2SO3; ΔH = - 42 kcal; the forward reaction will be favoured by
Low temperature
High pressure
Both (A) and (B)
Neither (A) nor (B)
In a turbine, the fluid expands almost
Isothermally
Isobarically
Adiabatically
None of these
A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is
Zero
Positive
Negative
None of these
When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the
Gibbs-Duhem equation
Gibbs-Helmholtz equation
Third law of thermodynamics
Joule-Thomson effect
Which law of the thermodynamics provides basis for measuring the thermodynamic property?
First law
Zeroth law
Third law
Second law
Chemical potential is a/an
Extensive property
Intensive property
Force which drives the chemical system to equilibrium
Both (B) and (C)
The principle applied in liquefaction of gases is
Adiabatic expansion
Joule-Thomson effect
Both (A) and (B)
Neither (A) nor (B)
Work done in an adiabatic process between two states depends on the
Rate of heat transmission
Initial state only
End states only
None of these
High pressure steam is expanded adiabatically and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ΔH and ΔS respectively for this process:
Δ H = 0 and ΔS = 0
Δ H ≠ 0 and ΔS = 0
Δ H ≠ 0 and ΔS ≠ 0
Δ H = 0 and ΔS ≠ 0
Extensive properties of a thermodynamic system depend upon the __________ of the system.
Specific volume
Temperature
Mass
Pressure
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
Which of the following is not correct for a reversible adiabatic process?
TVγ-1 = constant
p1-γ.TY = constant
PVγ = constant
None of these