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Explain the following: (a) The entropy...

Explain the following:
(a) The entropy of a substance increases on ging from the liquid to the vapour state at any temperature.
(b) Reactions with `Delta_(r)G^(@) lt 0` always have an equilibrium constant greater than 1.

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Comment on the following statements: (a) An exothermic reaction is always thermodynamically spontaneous. (b) Reaction with DeltaG^(@) lt 0 always have an equilibrium constant greater than 1.

Comment on the following statements: (a) An exothermic reaction is always thermodynamically spontaneous. Reaction with DeltaG lt O always have an equilibrium constant greater than 1

Effect of temperature on the equilibrium process analysed by using the thermodynamics From the thermodynamics reaction DeltaG^(@)=-2.30RTlogk DeltaG^(@): Standing free energy change DeltaG^(@)=DeltaH^(@)-TDeltaS^(@) …(ii) DeltaH^(@) : Standard heat of the reaction gt From eqns.(i) and(ii) -2RTlogk=DeltaH^(@)=TDeltaS^(@) DeltaS^(@) : standard entropy change implies" "logK=-(DeltaH^(@))/(2.3RT)+(DeltaS^(@))/(2.3R) Clearly, if a plot of k vs 1/T is made then it is a straight lone having slope =(-DeltaH^(@))/(2.3R) amd y intercept =(DeltaS^(@))/(2.3R) If at temperature T_(1) equilibrium constant be k_(1) and at temperature T_(2) equilibrium constant be k_(2) then : implies" "logK_(1)=-(DeltaH^(@))/(2.3RT_(1))+(DeltaS^(@))/(2.3R) ..(iv) implies" "logK_(2)=-(DeltaH^(@))/(2.3RT_(2))+(DeltaS^(@))/(2.3R) ...(v) Substracting e.q (iv) from (v), we get from the relation we can conclude that the of equilibrium constant increase in temperature for endothermic reaction eith but value of equilibrium constant decrease with the increase in temperature for exothermic reaction For exothermic reaction if DeltaS^(@)lt0 then the sketch of log k vs (1)/(T) may be

Effect of temperature on the equilibrium process analysed by using the thermodynamics From the thermodynamics reaction DeltaG^(@)=-2.30RTlogk DeltaG^(@): Standing free energy change DeltaG^(@)=DeltaH^(@)-TDeltaS^(@) …(ii) DeltaH^(@) : Standard heat of the reaction gt From eqns.(i) and(ii) -2RTlogk=DeltaH^(@)=TDeltaS^(@) DeltaS^(@) : standard entropy change implies" "logK=-(DeltaH^(@))/(2.3RT)+(DeltaS^(@))/(2.3R) Clearly, if a plot of k vs 1/T is made then it is a straight lone having slope =(-DeltaH^(@))/(2.3R) amd y intercept =(DeltaS^(@))/(2.3R) If at temperature T_(1) equilibrium constant be k_(1) and at temperature T_(2) equilibrium constant be k_(2) then : implies" "logK_(1)=-(DeltaH^(@))/(2.3RT_(1))+(DeltaS^(@))/(2.3R) ..(iv) implies" "logK_(2)=-(DeltaH^(@))/(2.3RT_(2))+(DeltaS^(@))/(2.3R) ...(v) Substracting e.q (iv) from (v), we get from the relation we can conclude that the of equilibrium constant increase in temperature for endothermic reaction eith but value of equilibrium constant decrease with the increase in temperature for exothermic reaction If for a particular reversible reaction K_(C)=57 abd 355^(@)C and K_(C)=69 at 450^(@)C then

Effect of temperature on the equilibrium process analysed by using the thermodynamics From the thermodynamics reaction DeltaG^(@)=-2.30RTlogk DeltaG^(@): Standing free energy change DeltaG^(@)=DeltaH^(@)-TDeltaS^(@) …(ii) DeltaH^(@) : Standard heat of the reaction gt From eqns.(i) and(ii) -2RTlogk=DeltaH^(@)=TDeltaS^(@) DeltaS^(@) : standard entropy change implies" "logK=-(DeltaH^(@))/(2.3RT)+(DeltaS^(@))/(2.3R) Clearly, if a plot of k vs 1/T is made then it is a straight lone having slope =(-DeltaH^(@))/(2.3R) amd y intercept =(DeltaS^(@))/(2.3R) If at temperature T_(1) equilibrium constant be k_(1) and at temperature T_(2) equilibrium constant be k_(2) then : implies" "logK_(1)=-(DeltaH^(@))/(2.3RT_(1))+(DeltaS^(@))/(2.3R) ..(iv) implies" "logK_(2)=-(DeltaH^(@))/(2.3RT_(2))+(DeltaS^(@))/(2.3R) ...(v) Substracting e.q (iv) from (v), we get from the relation we can conclude that the of equilibrium constant increase in temperature for endothermic reaction eith but value of equilibrium constant decrease with the increase in temperature for exothermic reaction If statndard heat of dissociation of PCl_(5) is 230 cal then slope of the graph of log vs (1)/(T) is :

Statement: The equilibrium constant for a reaction having positive DeltaH^(@) increases with increase of temperature. Explanation: The temperature dependence of the equilibrium constant is related to DeltaH^(@) and not DeltaS^(@) for the reaction.

The equilibrium constant K_(c) for A(g) hArr B(g) is 1.1 . Which gas has a molar concentration greater than 1 .

MODERN PUBLICATION-THERMODYNAMICS-Revision Exercise (Short Answer Questions)
  1. Explain the physical significance of entropy.

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  2. Predict the sign of DeltaS (positive or negative) for the following ch...

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  3. State giving reasons whether the entropy change for vaporisation of on...

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  4. What is entropy change?Predict the sign of entropy chsnge in each of t...

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  5. What is the value of free energy chnage for a reaction in equilibrium ...

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  6. Comment on the statement that the energy of the universe remains const...

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  7. Which of the reaction is expectd to be spontaneous at low temperatures...

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  8. Wha is menat by free energy of a system? How is it related to enthalpy...

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  9. State and explain Gibbs Helmholtz equation.

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  10. Predict or decrease of entropy : (a) Br(2)(g) to Br(g) (b) H(2)O(...

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  11. Predict the enthalpy change, free energy change and entropy change whe...

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  12. Define the terms: (i) Free energy (ii) Thermodynamic equilibrium ...

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  13. Neither the enthalpy change nor the entropy change alone can be used t...

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  14. Predict the sign of DeltaG for a reaction that is (a) Exothermic and...

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  15. What is Gibbs free energy change? Discuss its physical significance.

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  16. Explain the following: (a) The entropy of a substance increases on g...

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  17. How will you distinguish between the two? (i) Open and closed system...

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  18. What are spontaneous and non-spontaneous process? Under what condition...

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  19. What is free energy? How is it related to the spontaneity of a reactio...

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  20. Taking a specific example show that DeltaS("total") is the criterion f...

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