Description : For equilibrium process (i.e. reversible) in an isolated system (A) ds = 0 (B) ds < 0 (C) ds > 0 (D) ds = Constant
Last Answer : (A) ds = 0
Description : A change in state involving a decrease in entropy can be spontaneous, only if (A) It is exothermic (B) It is isenthalpic (C) It takes place isothermally (D) It takes place at constant volume
Last Answer : (A) It is exothermic
Description : Pick out the wrong statement: (A) The expansion of a gas in vacuum is an irreversible process (B) An isometric process is a constant pressure process (C) Entropy change for a reversible adiabatic process is zero (D) Free energy change for a spontaneous process is negative
Last Answer : (B) An isometric process is a constant pressure process
Description : Entropy change for an irreversible isolated system is (A) ∞ (B) 0 (C) < 0 (D) > 0
Last Answer : (D) > 0
Description : Pick out the wrong statement. (A) Cp of monatomic gases such as metallic vapor is about 5 kcal/kg.atom (B) The heat capacity of solid inorganic substance is exactly equal to the ... isolated system (D) At absolute zero temperature, the heat capacity for many pure crystalline substances is zero
Last Answer : (C) There is an increase in entropy, when a spontaneous change occurs in an isolated system
Description : For a spontaneous process, free energy (A) Is zero (B) Increases (C) Decreases whereas the entropy increases (D) And entropy both decrease
Last Answer : C) Decreases whereas the entropy increases
Description : Assertion :- Entropy of system increases for a spontaneous reactions. Reason :- Enthalpy of reaction always decreases for spontaneous reaction.
Last Answer : Assertion :- Entropy of system increases for a spontaneous reactions. Reason :- Enthalpy of reaction ... D. If both Assertion & Reason are false.
Description : In a spontaneous irreversible process the total entropy of the system and surroundings
Last Answer : In a spontaneous irreversible process the total entropy of the system and surroundings A. Remains constant B. Increases C. Decreases D. Zero
Description : If the rate of a chemical reaction becomes slower at a given temperature, then the (A) Initial concentration of the reactants remains constant (B) Free energy of activation is lower (C) Entropy changes (D) Free energy of activation is higher
Last Answer : (D) Free energy of activation is higher
Description : Assertion (A): May endothermic reactions that are not spontaneous at room temperature become spontaneous at high temperature. Reason (R ) : Entropy of
Last Answer : Assertion (A): May endothermic reactions that are not spontaneous at room temperature become spontaneous ... . If both Assertion & Reason are false.
Description : Spontaneous change is one in there is: (1) A lowering of entropy (2) A lowering of free energy (3) Increase in free energy (4) An increase in Internal energy
Last Answer : (2) A lowering of free energy Explanation: Entropy and enthalpy together make a new quantity, the Free Energy which, under conditions of constant temperature and pressure, determines the direction of spontaneous change. All spontaneous processes have a negative change in free energy.
Last Answer : A lowering of free energy
Description : Assertion :- In an isolated system the entropy increases due to spontanous process. Reason :- The processes in an isolated system are adiabatic.
Last Answer : Assertion :- In an isolated system the entropy increases due to spontanous process. Reason :- The ... D. If both Assertion & Reason are false.
Description : Two ideal gases under same pressure and temperature are allowed to mix in an isolated system. What will be the sign of entropy change?
Last Answer : Ans. Entropy change (∆S) is positive. It is because disorder or degree of freedom increases on mixing.
Description : A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system (A) its internal energy (U) decreases and its entropy (S) increases (B) U and S both decreases (C) U decreases but S is constant (D) U is constant but S decreases
Last Answer : (B) U and S both decreases
Description : For a spontaneous natural process at constant temperature and pressure, the free energy of the system always (A) Increases (B) Decreases (C) Remain constant (D) Increases to a maximum before decreasing
Last Answer : : Option A
Description : Entropy is a measure of the __________ of a system. (A) Disorder (B) Orderly behaviour (C) Temperature changes only (D) None of these
Last Answer : (A) Disorder
Description : A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, Δ S1 and Δ SR are the entropy changes of the system for the ... S1is sometimes > Δ SR (C) Δ S1is always > Δ SR (D) Δ S1is always = Δ SR
Last Answer : (C) Δ S1is always > Δ SR
Description : Third law of thermodynamics is helpful in (A) Prediction of the extent of a chemical reaction (B) Calculating absolute entropies of substances at different temperature (C) Evaluating entropy changes of chemical reaction (D) Both (B) and (C)
Last Answer : D) Both (B) and (C)
Description : Pick out the wrong statement. (A) The net change in entropy in any reversible cycle is always zero (B) The entropy of the system as a whole in an irreversible process increases (C) The ... to a maximum (D) The entropy of a substance does not remain constant during a reversible adiabatic change
Last Answer : (D) The entropy of a substance does not remain constant during a reversible adiabatic change
Description : As temperature goes to “0”, the entropy approaches a constant a. Zeroth Law of Thermodynamics b. First Law of Thermodynamics c. Second Law of Thermodynamics d. Third Law of Thermodynamics
Last Answer : Third Law of Thermodynamics
Description : Isentropic process means a constant __________ process. (A) Enthalpy (B) Pressure (C) Entropy (D) None of these
Last Answer : (C) Entropy
Description : Throttling (Joule-Thomson effect) process is a constant __________ process. (A) Enthalpy (B) Entropy (C) Pressure (D) None of these
Last Answer : (A) Enthalpy
Description : As the time is passing, entropy of the universe (A) Is increasing (B) Is decreasing (C) Remain constant (D) Data insufficient, can't be predicted
Last Answer : (A) Is increasing
Description : Specific __________ does not change during phase change at constant temperature and pressure. (A) Entropy (B) Gibbs energy (C) Internal energy (D) Enthalpy
Last Answer : (B) Gibbs energy
Description : Entropy of a substance remains constant during a/an __________ change. (A) Reversible isothermal (B) Irreversible isothermal (C) Reversible adiabatic (D) None of these
Last Answer : (C) Reversible adiabatic
Description : Throttling process is a/an __________ process. (A) Reversible and isothermal (B) Irreversible and constant enthalpy (C) Reversible and constant entropy (D) Reversible and constant enthalpy
Last Answer : (B) Irreversible and constant enthalpy
Description : During Joule-Thomson expansion of gases (A) Enthalpy remains constant (B) Entropy remains constant (C) Temperature remains constant (D) None of these
Last Answer : (A) Enthalpy remains constant
Description : Isobaric process means a constant process. (A) Temperature (B) Pressure (C) Volume (D) Entropy
Last Answer : (B) Pressure
Description : Joule-Thomson effect i.e., a throttling process is a constant __________ process. (A) Entropy (B) Temperature (C) Internal energy (D) Enthalpy
Last Answer : (D) Enthalpy
Description : If a solid is compressed adiabatically in its elastic range, its __________ remains constant (A) Internal energy (B) Enthalpy (C) Entropy (D) Temperature
Description : Superheating of steam is done at constant (A) Enthalpy (B) Entropy (C) Pressure (D) Volume
Last Answer : Option C
Description : Carnot cycle is also termed as the constant __________ cycle in thermodynamics. (A) Entropy (B) Pressure (C) Volume (D) Heat
Last Answer : Option D
Description : (i)State why heat changes in physical and chemical processes are indicated by enthalpy changes and not by entropy changes? (ii)What are the limitations of First Law of thermodynamics?
Last Answer : (i) Most of the processes are carried out in an open system i.e, at constant pressure. (ii)(a) Can’t explain the feasibility of the reaction. (b)It poses no restriction on the direction of flow of heat. (c)Practically it is not possible to convert the heat energy into an equivalent amount of work.
Description : Assertion :- Entropy is always constant for a closed system. Reason :- Closed system is always reversible.
Last Answer : Assertion :- Entropy is always constant for a closed system. Reason :- Closed system is always ... D. If both Assertion & Reason are false.
Description : Change in internal energy in a closed system is equal to heat transferred if the reversible process takes place at constant (a) pressure (b) temperature (c) volume (d) internal energy (e) entropy.
Last Answer : Answer : c
Description : Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant (a) pressure (b) temperature (c) volume (d) internal energy (e) entropy.
Last Answer : Answer : a
Description : According to first law of thermodynamics (a) work done by a system is equal to heat transferred by the system (b) total internal energy of a system during a process remains constant ( ... , enthalpy and entropy during a process remain constant (d) total energy of a system remains constant
Last Answer : Answer : d
Description : Change in enthalpy of a system is the heat supplied at (a) constant pressure (b) constant temperature (c) constant volume (d) constant entropy (e) N.T.P. condition.
Description : Maxwell's relation corresponding to the identity, dH = dS = Vdp + ∑μi dni is (A) (∂T/∂V)S, ni = -(∂P/∂S)V, ni (B) (∂S/∂P)T, ni = (∂V/∂T)P, ni (C) (∂S/∂V)T, ni = (∂P/∂T)V, ni (D) (∂T/∂P)S, ni = (∂V/∂S)P, ni
Last Answer : (D) (∂T/∂P)S, ni = (∂V/∂S)P, ni
Description : Vertical lines on pressure-enthalpy chart show constant (a) pressure lines (b) temperature lines (c) total heat lines (d) entropy lines
Last Answer : Ans: c
Description : On the pressure-enthalpy diagram, condensation and de-superheating is represented by a horizontal line because theprocess (a) takes place at constant pressure (b) takes place at constant temperature (c) takes place at constant entropy (d) takes place at constant enthalpy
Last Answer : Ans: a
Description : Short horizontal lines on pressure-enthalpy chart show (a) constant pressure lines (b) constant temperature lines (c) constant total heat lines (d) constant entropy lines
Description : The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.
Last Answer : ANSWER (c) two constant volume processes and two constant entropy processes
Description : Entropy of the universe is - (1) continuously increasing (2) continuously decreasing (3) zero (4) constant
Last Answer : (1) continuously increasing Explanation: In an irreversible process, entropy always increases, so the change in entropy is positive. The total entropy of the universe is continually increasing.
Description : What are the names given to constant temperature, constant pressure, constant volume, constant internal energy, constant enthalpy, and constant entropy processes.
Last Answer : Isothermal, isochroic, isobaric, free expression, throttling and adiabatic processes respectively.
Description : During which of following process does heat rejection take place in Carnot vapour cycle? [IES-1992] (a) Constant volume (b) constant pressure (c) Constant temperature (d) constant entropy
Last Answer : (c) Constant temperature
Description : Which of the following occurs in a reversible polytrophic process? a. Enthalpy remains constant b. Internal energy does not change c. Some heat transfer occurs d. Entropy remains constant
Last Answer : Some heat transfer occurs
Description : A process during which entropy remains constant is called ______ process A. Isometric B. Isochoric C. Isobaric D. Isentropic
Last Answer : Isentropic
Description : What is the energy absorbed during chemical reaction under constant volume conditions? A. Entropy B. Ion exchange C. Enthalpy D. Enthalpy of reaction
Last Answer : Enthalpy