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The difference between the reaction enthalpy change (ΔrH) and reaction internal energy change (ΔrU) for the reaction: 2C6H6(l) + 15O2(g) → 12CO2(g) + 6H2O(l) at 300 K is (R = 8.314 J mol−1 K−1)
- −24.942 kJ
- +24.942 kJ
- −12.471 kJ
- +12.471 kJ
Correct answer: +12.471 kJ
Solution
The difference between reaction enthalpy change (ΔrH) and internal energy change (ΔrU) is related to the work done by the system due to volume changes during the reaction, which can be calculated using the ideal gas law. In this case, the positive value indicates that the reaction produces more gas than it consumes, leading to an increase in enthalpy relative to internal energy.
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