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The enthalpy of elements in their standa...

The enthalpy of elements in their standard states are taken as zero. Hence the enthalpy of formation of a compound is

A

always negative

B

always positive

C

positive (or) negative

D

equal to zero

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The correct Answer is:
C
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AAKASH SERIES-CHEMICAL THERMODYNAMICS-Practice Sheet- Exercise-II
  1. Which are of the following is an exothermic reaction?

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  2. For which of the following elements, the standard enthalpy is not zero...

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  3. The enthalpy of elements in their standard states are taken as zero. H...

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  4. Enthalpy of neutralisation of all strong acids and strong bases has th...

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  5. The heats of combustion of carbon,hydrogen and acetylene are -394kJ, -...

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  6. The standard enthalpies of formation of H(2)O(2(l)) and H(2)O((l)) are...

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  7. Given C+ 2S rarr CS(2), DeltaHf^(0) = +117.0 KJ mol^(-1), C + O(2) rar...

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  8. The lattice energy of solid NaCl is 180K. Call per mol. The dissolutio...

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  9. The enthalpy of solution of BaCl(2)(s) and BaCl(2).2H(2)O(s) " are " -...

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  10. Hess's law states that

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  11. Equal volumes of equi molar HCl and H(2)SO(4) are separately neutralis...

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  12. The bond dissociation energies for Cl(2),I(2) and Icl are 242.3, 151 a...

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  13. Enthalpy of neutralisation of H(3)PO(3) acid is -106.68kJ//mol using N...

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  14. If DeltaH(f)^(0) " for" H(2)O(2(l)) and H(2)O((l)) " are " -188 kJ mol...

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  15. Chemical reactions are invariably associated with the transfer of ener...

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  16. Chemical reactions are invariably associated with the transfer of ener...

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  17. Chemical reactions are invariably assocated with the transfer of energ...

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  18. Chemical reactions are invariably assocated with the transfer of energ...

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  19. Match the following columns

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  20. Heats of atmoisation of ozone and oxygen are 25 units and 30 units res...

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