The energy of activation of exothermic reaction is
Zero
Negative
Very large compared to that for endothermic reaction
Not possible to predict
Correct Answer :
D. Not possible to predict
Related Questions
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
Less than
Equal to
More than
Either (B) or (C); depends on the type of alloy
As the temperature is lowered towards the absolute zero, the value of ∂(ΔF)/∂T, then approaches
Unity
Zero
That of the heat of reaction
Infinity
Which of the following has the minimum value of COP for a given refrigeration effect?
Reverse Carnot cycle
Ordinary vapour-compression cycle
Vapour-compression process with a reversible expansion engine
Air refrigeration cycle
At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by (where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)
μ° + RT ln f
μ°+ R ln f
μ° + T ln f
μ° + R/T ln f
Joule-Thomson co-efficient is defined as
μ = (∂P/∂T)H
μ = (∂T/∂P)H
μ = (∂E/∂T)H
μ = (∂E/∂P)H
Internal energy is equal to the heat absorbed in case of a/an __________ process.
Constant volume
Polytropic
Adiabatic
Constant pressure
Thermal efficiency of a Carnot engine can approach 100%, only when the temperature of the
Cold reservoir approaches zero
Hot reservoir approaches infinity
Either (A) or (B)
Neither (A) nor (B)
As the time is passing, entropy of the universe
Is increasing
Is decreasing
Remain constant
Data insufficient, can't be predicted
Equilibrium constant of a reaction varies with the
Initial concentration of the reactant
Pressure
Temperature
None of these
The thermodynamic law, PVy = constant, is not applicable in case of
Ideal compression of air
Free expansion of an ideal gas
Adiabatic expansion of steam in a turbine
Adiabatic compression of a perfect gas
Gibbs free energy of mixing at constant pressure and temperature is always
0
∞
+ ve
- ve
During Joule-Thomson expansion of gases
Enthalpy remains constant
Entropy remains constant
Temperature remains constant
None of these
Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.
Isothermal
Adiabatic
Isentropic
None of these
In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
Isothermal
Isobaric
Polytropic
Adiabatic
Consider the reaction, C + O2 CO2; ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO2 → C + O2?
-94 kcal
+94 kcal
> 94 kcal
< -94 kcal
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)
__________ explains the equilibrium constant for any chemical reaction.
Henry's law
Law of mass action
Hess's law
None of these
Pick out the wrong statement.
A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy.
An open system permits exchange of both mass and energy with its surroundings
The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics
None of the above
In the reaction; N2 + O2 2NO, increasing the pressure will result in
Shifting the equilibrium towards right
Shifting the equilibrium towards left
No change in equilibrium condition
None of these
Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2 (T1 > T2) is
T2/(T1 - T2)
T1/(T1 - T2)
(T1 - T2)/T1
(T1 - T2)/T2
In any spontaneous process, the __________ free energy decreases.
Helmholtz
Gibbs
Both a & b
Neither 'a' nor 'b'
__________ law of thermodynamics ascertains the direction of a particular spontaneous process.
Zeroth
First
Second
Third
The number of degree of freedom for an Azeotropic mixture of ethanol and water in vapourliquid equilibrium, is
3
1
2
0
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 any spontaneous process,
Only F decreases
Only A decreases
Both F and A decreases
Both F and A increase
Cv is given by
(∂E/∂T)V
(∂E/∂V)T
(∂E/∂P)V
(∂V/∂T)P
At the critical point of a substance
The surface tension vanishes
Liquid and vapour have the same density
There is no distinction between liquid and vapour phases
All (A), (B) and (C)
Pick out the correct statement.
The available energy in an isolated system for all irreversible (real) processes decreases
The efficiency of a Carnot engine increases, if the sink temperature is decreased
The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy
All (A), (B) and (C)
Third law of thermodynamics is helpful in
Prediction of the extent of a chemical reaction
Calculating absolute entropies of substances at different temperature
Evaluating entropy changes of chemical reaction
Both (B) and (C)
Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas)
T
√T
T2
1/√T