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JEE Main202117 Mar 2021Morning ShiftChemistryThermodynamics (C)Actual

The standard enthalpies of formation of Al 2 O 3 and CaO are - 1675 kJ mol - 1 and - 635 kJ mol - 1 respectively. For the reaction 3 CaO + 2 Al → 3 Ca + Al 2 O 3 the standard reaction enthalpy Δ r H 0 = ________ kJ . (Round off to the Nearest Integer).

Correct answer

0

Step-by-step solution

Given reaction: 3 CaO + Al → Al 2 O 3 + 3 Ca Now, Δ r H ° = ΣΔ f H Products  º - ΣΔ f H Reactants º = [ 1 × ( - 1675 ) + 3 × 0 ] - [ 3 × ( - 635 ) + 2 × 0 ] = + 230   kJ   mol - 1

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