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  3. Chemistry
  4. Calculate the standard enthalpy change (in kJ mol-1 ) for the reaction H2(g)+O2(g) xrightarrowH2O2(g) Given that bond enthalpies of H-H, text O=O, OH and OO (in kJ mol-1 ) are respectively 438, 498, 464 and 138.

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Q. Calculate the standard enthalpy change (in kJmol−1 ) for the reaction
H2(g)+O2(g)→H2O2(g)
Given that bond enthalpies of H−H, O=O, OH and OO (in kJ mol−1 ) are respectively 438,498,464 and 138.

KEAMKEAM 2010Thermodynamics

Solution:

H2(g)+O2(g)→H2O2(g)
ΔHreaction=BEreactants−BEproducts
=[BE(H−H)+BE(O=O)]
−2BE(O−H)+BE(O−O)]
=[438+498]−[2×464+138]
=936−1066=−130 kJ mol−1