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.
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 : 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 : 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 : Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.). (A) Entropy (B) Internal energy (C) Enthalpy (D) Gibbs free energy
Last Answer : (D) Gibbs free energy
Description : _________ does not change during phase transformation processes like sublimation, melting & vaporisation. (A) Entropy (B) Gibbs free energy (C) Internal energy (D) All (A), (B) & (C)
Last Answer : (B) Gibbs free energy
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 : 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 : 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 : For spontaneous changes in an isolated system (S = entropy) (A) ds = 0 (B) ds 0 (D) ds = Constant
Last Answer : (C) ds > 0
Description : Pick out the correct statement. (A) Like internal energy and enthalpy, the absolute value of standard entropy for elementary substances is zero (B) Melting of ice involves increase in enthalpy and ... of an ideal gas depends only on its pressure (D) Maximum work is done under reversible conditions
Last Answer : (D) Maximum work is done under reversible conditions
Description : What is defined as the sum of the system’s internal energy and the product of its pressure and volume? a. Entropy. b. Enthalpy. c. Free energy. d. Potential energy.
Last Answer : b. Enthalpy.
Description : Pick out the wrong statement. (A) Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point (B) Entropy of ... is negative for exothermic reactions (D) The eccentric factor for all materials is always more than one
Last Answer : (D) The eccentric factor for all materials is always more than one
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 is the measure of: a. The internal energy of a gas b. The heat capacity of a substance c. Randomness or disorder d. The change of enthalpy of a system
Last Answer : Randomness or disorder
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 : During throttling process (a) heat exchange does not take place (b) no work is done by expanding steam (c) there is no change of internal energy of steam (d) all of the above (e) entropy decreases.
Last Answer : Answer : d
Description : If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly (a) temperature (b) enthalpy (c) internal energy (d) entropy (e) all of the above.
Description : First law of thermodynamics (a) enables to determine change in internal energy of the system (b) does not help to predict whether the system will or not undergo a change (c) does not enable ... entropy (d) provides relationship between heat, work and internal energy (e) all of the above.
Last Answer : Answer : e
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 : When ice cubes are made, the entropy of water – (1) does not change (2) decreases (3) increases (4) may either increase or decrease depending on the process used
Last Answer : (2) decreases Explanation: When water is frozen into ice, the temperature drops below 0°C. Since the entropy of the solid is less than that of the liquid, the entropy of the water (the system ... decrease is found by dividing the heat of fusion of ice by the temperature for the reversible pathway.
Description : When ice cubes are made, the entropy of water (1) does not change (2) decreases (3) increases (4) may either increase or decrease depending on the process used
Last Answer : decreases
Description : Boiling of liquid is accompanied with increase in the (A) Vapor pressure (B) Specific Gibbs free energy (C) Specific entropy (D) All (A), (B) and (C)
Last Answer : (A) Vapor pressure
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 : Mollier diagram is a plot of (A) Temperature vs. enthalpy (B) Temperature vs. enthalpy (C) Entropy vs. enthalpy (D) Temperature vs. internal energy
Last Answer : (C) Entropy vs. enthalpy
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 : 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 : For an incompressible fluid, the __________ is a function of both pressure as well as temperature. (A) Internal energy (B) Enthalpy (C) Entropy (D) All (A), (B) & (C)
Last Answer : (B) Enthalpy
Description : If a solid is compressed adiabatically in its elastic range, its __________ remains constant (A) Internal energy (B) Enthalpy (C) Entropy (D) Temperature
Last Answer : (C) Entropy
Description : What is the measure of the energy that is no longer available to perform useful work within the current environment? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : entropy
Description : What is known as the total heat and heat content at various times in the history? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : enthalpy
Description : The sum of internal energy (U) and the product of pressure and volume (p.v) is known as A. workdone B. entropy C. enthalpy D. none of these
Last Answer : Answer: C
Description : Total heat of a substance is also known as (a) internal energy (b) entropy (c) thermal capacity (d) enthalpy (e) thermal conductance.
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
Description : Which of the following is the property of a system (a) pressure and temperature (b) internal energy (c) volume and density (d) enthalpy and entropy (e) all of the above.
Description : The Gibbs free energy change of a reaction at `27^(@)C` is -26 Kcal. and its entropy change is -60 Cals/K. `Delta H` for the reaction is :-
Last Answer : The Gibbs free energy change of a reaction at `27^(@)C` is -26 Kcal. and its entropy change is -60 Cals/K. ... Cals. C. 34 K. Cals. D. `-24` K. Cals.
Description : (∂H/∂T)P is the mathematical expression for (A) CV (B) Entropy change (C) Gibbs free energy (D) None of these
Last Answer : (D) None of these
Description : What American first proposed the free energy function G, which interrelates entropy and enthalpy?
Last Answer : ANSWER: J. WILLARD GIBBS
Description : In any chemical reaction, a quantity that decrease to a minimum is: w) free energy x) entropy y) temperature z) enthalpy
Last Answer : ANSWER: W -- FREE ENERGY
Description : In which of the following reactions, standard reaction entropy change (S°) is positive and standard Gibb's energy change (G°) decreases sharply with increasing temperature? (1) 2 2 1 1 1 C graphite O (g) CO (g) 2 2 2 (2) 2 1 C ... CO(g) O (g) CO (g) 2 (4) 2 1 Mg(s) O (g) MgO(s) 2
Last Answer : C graphite O (g) CO(g)
Description : What is spontaneous change? Give one example.
Last Answer : Ans. A process which can take place of its own or upon initiation under some condition. eg. Common salt dissolves in water of its own.
Description : In any spontaneous process, the __________ free energy decreases. (A) Helmholtz (B) Gibbs (C) Both ‘a’ & ‘b’ (D) Neither 'a' nor 'b'
Last Answer : (C) Both ‘a’ & ‘b’
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 : Melting of wax is accompanied with __________ in entropy. (A) Increase (B) Decrease (C) No change (D) None of these
Last Answer : (A) Increase
Description : An enzyme promotes a chemical reaction by (A) Lowering the energy of activation (B) Causing the release of heat which acts as a primer (C) Increasing molecular motion (D) Changing the free energy difference between substrate and product
Last Answer : Answer : A
Description : In __________ process, there is an increase in entropy with no degradation of energy. (A) Isothermal expansion (B) Isochoric heat addition (C) Polytropic expansion (D) Isobaric heat addition
Last Answer : (A) Isothermal expansion
Description : Increase in the entropy of a system represents the (A) Degradation of energy (B) Decrease in system pressure (C) Increase in the availability of energy (D) Increase in the temperature
Last Answer : Option A
Description : What is considered as the heat content of a system? A. Enthalpy B. Entropy C. Internal heat D. Molar heat
Last Answer : Enthalpy