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Hydrogen iodide (HI) is formed from the reaction of the elements hydrogen and iodine H₂(g) + I₂(g) → 2HI(g); ΔH = +52 kJ mol⁻¹ When two moles of HI decompose A - VCE - SSCE Chemistry - Question 3 - 2006 - Paper 1
Question 3
Hydrogen iodide (HI) is formed from the reaction of the elements hydrogen and iodine H₂(g) + I₂(g) → 2HI(g); ΔH = +52 kJ mol⁻¹ When two moles of HI decompose A. 5... show full transcript
Worked Solution & Example Answer:Hydrogen iodide (HI) is formed from the reaction of the elements hydrogen and iodine H₂(g) + I₂(g) → 2HI(g); ΔH = +52 kJ mol⁻¹ When two moles of HI decompose A - VCE - SSCE Chemistry - Question 3 - 2006 - Paper 1
Step 1
When two moles of HI decompose
Answer
To understand the energy changes during the decomposition of hydrogen iodide (HI), one needs to consider the given enthalpy change (ΔH) in the reaction. The enthalpy change provided is associated with the formation of HI from hydrogen and iodine, which is an endothermic process, as indicated by the positive sign (+52 kJ mol⁻¹).
When HI decomposes back into its constituent elements, the reverse of the reaction occurs. Thus, it will release energy equal to the enthalpy change for formation. Given that the formation of 2 moles of HI absorbs 52 kJ, the decomposition of 2 moles of HI will release the same amount of energy, which is 52 kJ for the 2 moles.
Therefore, if we consider two moles of HI decomposing:
- The answer would therefore be that 52 kJ of energy is released during the decomposition process. Thus, the correct answer is A, indicating that 52 kJ of energy is released.