Gibbs Free Energy & Spontaneity
The equilibrium constant for a reaction is 10. What will be the value of Δ Gθ? R=8.314 JK−1mol−1T=300K.
A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(iv) possible at any temperature
For the reaction
2A(g)+B(g)→2D(g)Δ Uθ=−10.5 kJ and Δ Sθ=–44.1 JK−1.
Calculate Δ Gθ for the reaction, and predict whether the reaction may occur spontaneously.
Count Function in SQL Returns the Number of
- T > 425 K
- All temperatures
- T < 425 K
- T > 298 K
Given: △r H298K=−54.07 kJ mol−1, △rSo298K=10 J K−1 mol−1 and R=8.314 J K−1mol−1; 2.303×8.314×298=5705).
Which of the following is affected by catalyst?
[Given: The standard enthalpy change for the reaction is –165 kJ mol–1]. The temperature in K at which the reaction attains equilibrium is
- T△S<△H and both △H, △S are +ve
- T△S<△H and △H=+ve, △S=−ve
- T△S>△H and both △H, △S are +ve
- T△S=△H and both △H, △S are +ve
Out of C and CO, which is a better reducing agent for ZnO ?
For which △rHo=+491.1kJ mol−1and△rS∘=198.0JK−1mol−1 is not feasible at 298 K. Temperature above which reaction will be feasible is
At 298 K, Kp for reaction N2O4(g)⇌2NO2(g) is 0.98. Predict whether the reaction is spontaneous or not.
Given below are two statements:
Statement 1: The value for is
Statement 2: is more stable in state than state
Both statement 1 and statement 2 are correct
Statement 1 is incorrect but statement 2 is correct
Both statement 1 and statement 2 are incorrect
Statement 1 is correct but statement 2 is incorrect
- No change in volume on mixing. ΔVmix=0
- No change in enthalpy on mixing. ΔHmix=0
- Entropy on mixing ΔSmix>0
- All of the above.
Is activation energy dependent on temperature?
(R=8.314 JK/mol, e=2.718)
- Forward direction because Q>Kc
- Forward direction because Q<Kc
- Reverse direction because Q<Kc
- Reverse direction because Q>Kc
the standard Gibbs free energy of reaction (at 1000 K) is −8.1 kJ/mol. Calculate its equilibrium constant
△H=−95.4 kJ and △S=−198.3 JK−1
Calculate the temperature at which Gibb's energy change (△G) is equal to zero.
- 495 K
- 430 K
- 450 K
- 481 K
Which of the following is not correct?
(a) Δ G is zero for a reversible reaction.
(b) Δ G is positive for a spontaneous reaction.
(c) Δ G is negative for a spontaneous reaction.
(d) Δ G is positive for a non-spontaneous reaction.
- 1.728 kJ mol−1 K−1
- −1.728 kJ mol−1 K−1
- 0.75 kJ mol−1 K−1
- 80 cal
- 540 cal
- 620 cal
- Endothermic if A > 0
- Exothermic if B < 0
- Exothermic if A > 0 and B < 0
- Endothermic if A < 0 and B > 0
What is intensive and extensive properties of thermodynamics?
- △H>0, △S>0
- △H>0, △S<0
- △H<0, △S>0
- △H<0, △S<0