Description : The enthalpy changes at 298 K in successive breaking of `O-H` bonds of water, are `H_(2)O(g) rarr H(g)+OH(g),DeltaH=498kJ mol^(-1)` `OH(g) rarr H(g)+O
Last Answer : The enthalpy changes at 298 K in successive breaking of `O-H` bonds of water, are `H_(2)O(g) rarr H(g)+OH(g), ... KJ mol"^(-1)` D. `463 "KJ mol"^(-1)`
Description : If a reaction has an enthalpy of -54.32 kJ/mol and an entropy of -354.2 J/(K*mol), what is the Gibbs free Energy at 54.3(degrees c)?
Last Answer : DeltaG = DeltaH - TDeltaS dG = -54.32 kJ/mol - (54'32+273)K(-354.2J/molK) NB Thevtemperature is quoted in Kelvin(K) and the Entropy must be converted to kJ by dividing by '1000'/ Hence dG = ... 115.94 kJ/mol dG = (+)61.61 kJ/mol Since dG is positive, the reaction is NOT thermodynamically feasible.
Description : What is the standard enthalpy change at 298 K for the following reaction? `CO_(2) (g)+ C("diamond") rarr 2CO(g)` Given : `DeltaH_(f)^(@)(CO,g) = - 110
Last Answer : What is the standard enthalpy change at 298 K for the following reaction? `CO_(2) (g)+ C("diamond") rarr 2CO(g ... `+172.5 kJ//mol` D. `170.5 kJ//mol`
Description : The enthalpy and entropy change for the reaction, `Br_(2)(l)+Cl_(2)(g)rarr2BrCl(g)` are `30KJmol^(-1)` and `105JK^(-1)mol^(-1)` respectively. The temp
Last Answer : The enthalpy and entropy change for the reaction, `Br_(2)(l)+Cl_(2)(g)rarr2BrCl(g)` are `30KJmol^(-1)` and ` ... 285.7 K B. 273 K C. 450 K D. 300 K
Description : The enthalpy change `(Delta H)` for the reaction `N_(2) (g)+3H_(2)(g) rarr 2NH_(3)(g)` is `-92.38 kJ` at `298 K`. What is `Delta U` at `298 K`?
Last Answer : The enthalpy change `(Delta H)` for the reaction `N_(2) (g)+3H_(2)(g) rarr 2NH_(3)(g)` is `-92.38 kJ` at ` ... -87.42 kJ` C. `-97.34 kJ` D. `-89.9 kJ`
Description : Given that the standard free energy change (∆G°) for the hydrolysis of ATP is -7.3 K cal/mol and that for the hydrolysis of Glucose 6-phosphate is -3.3 Kcal/mol, the ∆G° for the phosphorylation of glucose is Glucose + ATP → ... -10.6 Kcal/mol (B) -7.3 Kcal/mol (C) -4.0 Kcal/mol (D) +4.0 Kcal/mol
Last Answer : Answer : C
Description : For a reaction `2X(s)+2Y(s)rarr 2Cl(l)+D(g)` The `q_(p)` at `27^(@)C` is -28 K Cal. `mol^(-1)`. The `q_(V)` is ___________ K. Cal. `mol^(-1)` :-
Last Answer : For a reaction `2X(s)+2Y(s)rarr 2Cl(l)+D(g)` The `q_(p)` at `27^(@)C` is -28 K Cal. `mol^(-1)`. The `q_( ... . `-27.4` B. `+27.4` C. `-28.6` D. `28.6`
Description : If the enthalpy of vaporisation of water is `186.5 J mol^(-1)`, then entropy of its vaporisation will be
Last Answer : If the enthalpy of vaporisation of water is `186.5 J mol^(-1)`, then entropy of its vaporisation will be A. `0.5 ... (-1)` D. `2.0KJK^(-1)"mole"^(-1)`
Description : Calculate the enthalpy of vaporisation per mole for ethanol. Given `DeltaS = 109.8 J K^(-1) mol^(-1)` and boiling point of ethanol is `78.5^(@)`.
Last Answer : Calculate the enthalpy of vaporisation per mole for ethanol. Given `DeltaS = 109.8 J K^(-1) mol^(-1)` ... KJ mol^(-1)` D. Some more data is required
Description : The enthalpy of formation of ammonia is `-46.0 KJ mol^(-1)` . The enthalpy change for the reaction `2NH_(3)(g)rarr N_(2)(g)+3H_(2)(g)` is :
Last Answer : The enthalpy of formation of ammonia is `-46.0 KJ mol^(-1)` . The enthalpy change for the reaction `2NH_(3)(g) ... mol^(-1)` D. `-92.0 KJ mol^(-1)`
Description : The value of enthalpy change `(DeltaH)` for the reaction `C_(2)H_(5)OH (l)+3O_(2) (g) rarr 2CO_(2) (g) +3H_(2)O (l)` at `27^(@)C` is `-1366.5 kJ mol^(
Last Answer : The value of enthalpy change `(DeltaH)` for the reaction `C_(2)H_(5)OH (l)+3O_(2) (g) rarr 2CO_(2) (g) + ... 1369. kJ` C. `-1364.0 kJ` D. `-1361.5 kJ`
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 state occurs in isentropic process a. The change in entropy is 0 b. The change in entropy is 1 c. The change in enthalpy is 0 d. The change in enthalpy is 1
Last Answer : The change in entropy is 0
Description : What is meant by entropy driven reaction? How can the reaction with positive change of enthalpy and entropy be made entropy driven?
Last Answer : Ans.The free energy change of a reaction is given by ΔG = ΔH - TΔS For a reaction to be spontaneous, ΔG should be -ve. If both ΔH and ΔS are positive ΔG can be -ve if TΔS>ΔH in magnitude. Thus, entropy ... is low, TΔS should be greater than ΔH (ii) If ΔS is small, T should be so large that TΔS>ΔH.
Description : Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of (A) Solution (B) Vaporisation (C) Formation (D) Sublimation
Last Answer : (B) Vaporisation
Description : The enthalpy of formation of `CO(g), CO_(2)(g),N_(2)O(g)` and `N_(2)O_(4)(g)` is `-110,-393,+81` and 10 kJ / mol respectively. For the reaction `N_(2)
Last Answer : The enthalpy of formation of `CO(g), CO_(2)(g),N_(2)O(g)` and `N_(2)O_(4)(g)` is `-110,-393,+81` and 10 ... is A. `-212` B. `+212` C. `+778` D. `-778`
Description : Standard entropy of `X_(2)` , `Y_(2)` and `XY_(3)` are `60, 40 ` and `50JK^(-1)mol^(-1)` , respectively. For the reaction, `(1)/(2)X_(2)+(3)/(2)Y_(2)r
Last Answer : Standard entropy of `X_(2)` , `Y_(2)` and `XY_(3)` are `60, 40 ` and `50JK^(-1)mol^(-1)` , respectively ... be: A. 500 K B. 750 K C. 1000 K D. 1250 K
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 : The standard free energy of hydrolysis of terminal phosphate group of ATP is (A) –7,300 cal/mol (B) –8,300 cal/mol (C) 10,000 cal/mol (D) +7,300 cal/mol
Last Answer : A
Description : The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3 is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit ... /kmole. K (may be assumed to be independent of temperature)) (A) 400 (B) 500 (C) 600 (D) 1000
Last Answer : (C) 600
Description : For the irreversible reaction, Ca+ 2C = Ca C2, Δ H°298 = - 60000 J . mole-1. If a system initially containing 2 moles of calcium, 3 moles of carbon and 1 mole of calcium carbide is allowed to react to completion, the heat evolved ... will be (A) 30,000 J (B) 60,000 J (C) 90,000 J (D) 2,40,000 J
Last Answer : (C) 90,000 J
Description : Burning of Gasoline initially requires heat before it burns spontaneously. Which of the following does not give a good explanation of this phenomenon? a. the initial heat rises the enthalpy of the reactant ... of products. d. The enthalpy of the product is lower than the enthalpy of the reactant
Last Answer : the enthalpy of reactants is lower than the enthalpy of products.
Description : Given standard enthalpy of formation of `CO(-110 "KJ mol"^(-1))` and `CO_(2)(-394 "KJ mol"^(-1))`. The heat of combustion when one mole of graphite bu
Last Answer : Given standard enthalpy of formation of `CO(-110 "KJ mol"^(-1))` and `CO_(2)(-394 "KJ mol"^(-1))`. The heat ... B. `-284` KJ C. `-394` KJ D. `-504` KJ
Description : Given that standard heat enthalpy of `CH_(4), C_(2)H_(4)` and `C_(3)H_(8)` are -17.9, 12.5, -24.8 Kcal/mol. The `Delta H` for `CH_(4)+C_(2)Hrarr C_(3)
Last Answer : Given that standard heat enthalpy of `CH_(4), C_(2)H_(4)` and `C_(3)H_(8)` are -17.9, 12.5, -24.8 Kcal ... . `-30.2` Kcal C. 55.2 Kcal D. `-19.4` Kcal
Description : Entropy of the system decreases, when (A) Snow melts into water (B) A gas expands spontaneously from high pressure to low pressure (C) Water is converted into ice (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
Description : `Delta_(f)^(@)` for `CO_(2(g)), CO_((g))` and `H_(2)O_((g))` are `-393.5,-110.5` and `-241.8kJ mol^(-1)` respectively. The standard enthalpy change `(
Last Answer : `Delta_(f)^(@)` for `CO_(2(g)), CO_((g))` and `H_(2)O_((g))` are `-393.5,-110.5` and `-241.8kJ mol^(-1 ... A. `524.1` B. `41.2` C. `-262.5` D. `-41.2`
Description : Standard enthalpy of formation of ethane is -84.7kjper mol calculate the enthalpy change for the formation of 0.1kg ethane
Last Answer : Standard enthalpy of formation of ethane is -84.7kjper mol calculate the enthalpy change for the formation of 0.1kg ethane
Description : If the enthaply change for the transition of liquid water to steam is 30 KJ `"mol"^(-1)` at `27^(@)` C . The entropy change for the process would be
Last Answer : If the enthaply change for the transition of liquid water to steam is 30 KJ `"mol"^(-1)` at `27^(@)` C . The ... K^(-1)` D. `100 J mol^(-1)K^(-1)`
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 : The first law of thermodynamics is based on which of the following principles? a. conservation of mass b. the enthalpy-entropy relationship c. action – reaction d. conservation of energy
Last Answer : conservation of energy
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
Description : For the given reaction , `A(g) rarr 2B(g) , Delta_(r)H= 30 kJ//"mole" Delta_(r)S = 150 J//mol` at `300 K` If `C_(P,A) = 20 J//K mol` and `C_(P,B) = 20
Last Answer : For the given reaction , `A(g) rarr 2B(g) , Delta_(r)H= 30 kJ//"mole" Delta_(r)S = 150 J//mol` at ... G` is negative D. At `T = 200, Delta G` is zero
Description : A 500 mL glass flask is filled at 298 K and 1 atm, pressure with three diatomic gases, X, Y and Z . The initial volume ratio of the gases before mixin
Last Answer : A 500 mL glass flask is filled at 298 K and 1 atm, pressure with three diatomic gases, X, Y and Z . The ... . `H_2 , F_2 , O_2` D. `O_2,H_2 , F_2`
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 : What refers to the measure of the disorder present in a given substance or system? A. Enthalpy B. Entropy C. Heat capacity D. Molar heat
Last Answer : Entropy
Description : Which of the following parameters is constant for a mole for most of the gases at a given temperature and pressure (a) enthalpy (b) volume (c) mass (d) entropy (e) specific volume.
Last Answer : Answer : b
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 : 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: ... (C) Δ H ≠ 0 and ΔS ≠ 0 (D) Δ H = 0 and ΔS ≠ 0
Last Answer : (B) Δ H ≠ 0 and ΔS = 0
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 : 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 : The change that the system that undergoes from one equilibrium state to another is known as a. oath b. process c. enthalpy change d. entropy change
Last Answer : process
Description : Regardless of the process, the change in enthalpy firm moles of ideal gas is a. Heat b. Enthalpy c. Entropy d. Density
Last Answer : Heat
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.
Last Answer : Answer : d
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 : 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 : Heat of reaction for, `CO(g)+1//2O_(2)(g)rarr CO_(2)(g)` at constant V is -67.71 K cal at `17^(@)C` . The heat of reaction at constant P at `17^(@)C`
Last Answer : Heat of reaction for, `CO(g)+1//2O_(2)(g)rarr CO_(2)(g)` at constant V is -67.71 K cal at `17^(@)C` . ... B. `+68.0` K cal C. `-67.4` K cal D. None
Description : The enthalpy of combustion of `H_(2)` , cyclohexene `(C_(6)H_(10))` and cyclohexane `(C_(6)H_(12))` are `-241` , `-3800` and `-3920KJ` per mol respect
Last Answer : The enthalpy of combustion of `H_(2)` , cyclohexene `(C_(6)H_(10))` and cyclohexane `(C_(6)H_(12))` are `-241 ... "KJ mol"^(-1)` D. `242 "KJ mol^(-1)`
Description : Ionization enthalpy of Li is 520 kJ mol^(-1) while that of F is 1681 kJ mol^(-1) . Explain.
Last Answer : Ionization enthalpy of Li is 520 kJ mol-1 while that of F is 1681 kJ mol-1. Explain.
Description : If your room has a natural tendency to become messy and disordered, it is an excellent example of: w) enthalpy x) entropy y) the Bernoulli effect z) the Haase effect
Last Answer : ANSWER: X -- ENTROPY
Description : It is a common observation that naturally occurring processes have a particular direction associated with them. For instance, heat flows from a hot body to a colder body. The property of a system ... this natural direction of events is called w) energy x) entropy y) enthalpy z) equilibrium