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Why standard entropy of an elementary su...

Why standard entropy of an elementary substance is not zero whereas standard enthalpy of formation is taken as zero?

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A substance has a perfectly ordered arrangement only at absolute zero. Hence, entropy is zero only at absolute zero. Enthalpy of formation is the heat change involved in the formation of one mole of the substance from its elements. An element formed from its constituents means no heat change.
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FULL MARKS-THERMODYNAMICS -Additional Questions Solved (II) Answer briefly
  1. Define molar heat of fusion.

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  2. What is meant by molar heat of vaporization?

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  3. (i) What is sublimation? (ii) Define molar heat of sublimation.

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  4. Define heat of transition?

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  5. How do you measure the enthalpy of formation of carbon monoxide?

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  6. What are the Important features of lattice enthalpy?

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  7. Why there is need for second law of thermodynamics? Give its importanc...

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  8. Write the entropy statement of second law of thermodynamics.

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  9. State Clausius form of the second law of thermodynamics.

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  10. What are spontaneous reaction? Give three examples for spontaneous rea...

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  11. Calculate the standard entropy of formation DeltaS(f)^(@) " of "CO(2((...

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  12. What is entropy of fusion?

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  13. What is entropy of Vaporization?

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  14. Define entropy of transition.

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  15. Explain the following: (i)Out of diamond and graphite, which has gre...

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  16. What is the condition spontaneity in terms of free energy change?

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  17. Why standard entropy of an elementary substance is not zero whereas st...

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  18. The equilibrium constant for a reaction is one or more if DeltaG^Ө for...

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  19. Many thermodynamically feasible reactions do not occur under ordinary ...

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  20. Predict in which of the following , entropy increases or decreases . ...

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