Thermodynamics
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Match the following parameters with description for spontaneity:
Match the following parameters with description for spontaneity:
This is a Matching Type Questions as classified in NCERT Exemplar
(i)- (c)
(ii)- (a)
(iii)- (b)
Upvote 
Match the following processes with entropy change:
Match the following processes with entropy change:
This is a Matching Type Questions as classified in NCERT Exemplar
(i) (b)
(ii) (c)
(iii) (a)
Upvote 
Consider the following reaction between zinc and oxygen and choose the correct options out of the options given below:
2Zn(s) + O2(g) → 2ZnO (s) ; ∆H = – 693.8 kJ/mol
(i) The enthalpy of two moles of ZnO is less than the total enthalpy of two moles of Zn and one mole of oxygen by 693.8 kJ.
(ii) The enthalpy of two moles of ZnO is more than the total enthalpy of two moles of Zn and one mole of oxygen by 693.8 kJ.
(iii) 8 kJ mol–1 energy is evolved in the reaction.
(iv) 8 kJ mol–1 energy is absorbed in the reaction.
Consider the following reaction between zinc and oxygen and choose the correct options out of the options given below:
2Zn(s) + O2(g) → 2ZnO (s) ; ∆H = – 693.8 kJ/mol
(i) The enthalpy of two moles of ZnO is less than the total enthalpy of two moles of Zn and one mole of oxygen by 693.8 kJ.
(ii) The enthalpy of two moles of ZnO is more than the total enthalpy of two moles of Zn and one mole of oxygen by 693.8 kJ.
(iii) 8 kJ mol–1 energy is evolved in the reaction.
(iv) 8 kJ mol–1 energy is absorbed in the reaction.
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (i) and (iii)
Upvote For an ideal gas, the work of reversible expansion under isothermal condition can be calculated by using the expression w= -nRTln
A sample containing 1.0 mol of an ideal gas is expanded isothermally and reversibly to ten times of its original volume, in two separate experiments. The expansion is carried out at 300 K and at 600 K respectively. Choose the correct option.
(i) Work done at 600 K is 20 times the work done at 300 K.
(ii) Work done at 300 K is twice the work done at 600 K.
(iii) Work done at 600 K is twice the work done at 300 K.
(iv) ∆U = 0 in both cases.
For an ideal gas, the work of reversible expansion under isothermal condition can be calculated by using the expression w= -nRTln
A sample containing 1.0 mol of an ideal gas is expanded isothermally and reversibly to ten times of its original volume, in two separate experiments. The expansion is carried out at 300 K and at 600 K respectively. Choose the correct option.
(i) Work done at 600 K is 20 times the work done at 300 K.
(ii) Work done at 300 K is twice the work done at 600 K.
(iii) Work done at 600 K is twice the work done at 300 K.
(iv) ∆U = 0 in both cases.
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (iv)
For
isothermal reversible change
q= -w = nRTln =2.303nRTlog
= = =2
For
isothermal expansion of ideal gases, ? U = 0
Since,
temperature is constant this means there is no change in internal energy.
Upvote The spontaneity means, having the potential to proceed without the assistance of external agency. The processes which occur spontaneously are (i) flow of heat from colder to warmer body. (ii) Gas in a container contracting into one corner. (iii) Gas expanding to fill the available volume. (iv) Burning carbon in oxygen to give carbon dioxide.
The spontaneity means, having the potential to proceed without the assistance of external agency. The processes which occur spontaneously are (i) flow of heat from colder to warmer body. (ii) Gas in a container contracting into one corner. (iii) Gas expanding to fill the available volume. (iv) Burning carbon in oxygen to give carbon dioxide.
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (iii) and (iv)
Gas expands to fill the available space spontaneously, and burning of carbon to carbon dioxide is spontaneous
Upvote In an exothermic reaction, heat is evolved, and system loses heat to the surroundings. For such system
(i) qp will be negative
(ii) ∆rH will be negative
(iii) qp will be positive
(iv) ∆rH will be positive
In an exothermic reaction, heat is evolved, and system loses heat to the surroundings. For such system
(i) qp will be negative
(ii) ∆rH will be negative
(iii) qp will be positive
(iv) ∆rH will be positive
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (i) and (ii)
In an exothermic reaction, heat is evolved, and system loses heat to the surroundings. Therefore, qp will be negative and? rH will also be negative. Hence, option (i) and (ii) is the correct answer.
Upvote Thermodynamics mainly deals with
(i) Interrelation of various forms of energy and their transformation from one form to another.
(ii) Energy changes in the processes which depend only on initial and final states of the microscopic systems containing a few molecules.
(iii) How and at what rate these energy transformations are carried out.
(iv) The system in equilibrium state or moving from one equilibrium state to another equilibrium state.
Thermodynamics mainly deals with
(i) Interrelation of various forms of energy and their transformation from one form to another.
(ii) Energy changes in the processes which depend only on initial and final states of the microscopic systems containing a few molecules.
(iii) How and at what rate these energy transformations are carried out.
(iv) The system in equilibrium state or moving from one equilibrium state to another equilibrium state.
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (i)
The laws of thermodynamics deal with energy changes of macroscopic systems involving a large number of molecules rather than microscopic systems containing a few molecules. Laws of thermodynamics apply only when a system is
Upvote Which of the following is not correct?
(i) ∆G is zero for a reversible reaction
(ii) ∆G is positive for a spontaneous reaction
(iii) ∆G is negative for a spontaneous reaction
(iv) ∆G is positive for a non-spontaneous reaction
Which of the following is not correct?
(i) ∆G is zero for a reversible reaction
(ii) ∆G is positive for a spontaneous reaction
(iii) ∆G is negative for a spontaneous reaction
(iv) ∆G is positive for a non-spontaneous reaction
This is a Multiple Choice Questions as classified in NCERT Exemplar
option (ii)
positive for a spontaneous reaction
Upvote Enthalpy of sublimation of a substance is equal to
(i) Enthalpy of fusion + enthalpy of vapourisation
(ii) Enthalpy of fusion
(iii) Enthalpy of vapourisation
(iv) Twice the enthalpy of vapourisation
Enthalpy of sublimation of a substance is equal to
(i) Enthalpy of fusion + enthalpy of vapourisation
(ii) Enthalpy of fusion
(iii) Enthalpy of vapourisation
(iv) Twice the enthalpy of vapourisation
This is a Multiple Choice Questions as classified in NCERT Exemplar
Option (i)
Enthalpy of sublimation can be shown as
Solid | Liquid | Vapour
Hence, Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vaporisation.
Upvote