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Why does the value of DeltaH for a chemi...

Why does the value of `DeltaH` for a chemical reaction depend on the physical states of the reaction(s) and product(s)?

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In case of solids and liquids, `DeltaH=DeltaU` for a chemical reaction (as `DeltaV` is negligible here). If the participating substances are gases, then `DeltaH=DeltaU+DeltanRT`. Hence, `DeltaH` for a chemical reaction depends on the physical states of the reactant(s) and product(s).
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CHHAYA PUBLICATION-CHEMICAL THERMODYNAMICS-WARM UP EXERCISE
  1. Mention the standard states of the following elements at 25^(@)C and 1...

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  2. Why is DeltaH=DeltaU for the following two reactions? Explain. (i) N...

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  3. Why does the value of DeltaH for a chemical reaction depend on the phy...

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  4. Give an example of a reaction for each of the following relations betw...

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  5. Give an example of a physical change for each of the following relatio...

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  6. For which element in each of the following pairs has the standard heat...

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  7. In which of the following reactions At 25^(@)C, does the standard enth...

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  8. Which one of the given reactions indicates the formation reaction of t...

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  9. At 25^(@)C the standard heat of formation of liquid benzene is +49.0 k...

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  10. The standard heat of combustion of solid naphthalene [C(10)H(8)(s)] at...

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  11. Give an example of a combustion reaction whose standard enthalpy chang...

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  12. The standard enthalpy of combustion of C(x)H(y)(l) at 25^(@)C is Q kJ*...

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  13. The standard heats of combustion of CH(4)(g) and C(2)H(6)(g) are -890k...

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  14. Define: (i) Enthalpy of fusion, (ii) Enthalpy of vaporisation, (iii) E...

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  15. Identify whether the enthalpy of the initial state is greater than, le...

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  16. At a given temperature and pressure, the enthalpies of condensation an...

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  17. Why are the changes in enthalpies for the given processes the same? (i...

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  18. What does DeltaH signify in each of the following equations? (i) HCl...

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  19. Change in enthalpy remains the same whether a reaction is carried out ...

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  20. Given (at 25^(@)C and 1 atm pressure): C(s, diamond)+O(2)(g)toCO(2)(...

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