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Nitrogen dioxide decomposes as follows - VCE - SSCE Chemistry - Question 5 - 2012 - Paper 1
Question 5
Nitrogen dioxide decomposes as follows. 2NO₂(g) → N₂(g) + 2O₂(g) ∆H = -66 kJ mol⁻¹ The enthalpy change for the reaction represented by the equation \(\frac{1}{2}N₂... show full transcript
Worked Solution & Example Answer:Nitrogen dioxide decomposes as follows - VCE - SSCE Chemistry - Question 5 - 2012 - Paper 1
Step 1
The enthalpy change for the reaction represented by the equation \(\frac{1}{2}N₂(g) + O₂(g) → NO₂(g)\)
Answer
To find the enthalpy change for the reaction (\frac{1}{2}N₂(g) + O₂(g) → NO₂(g)), we can use the provided reaction enthalpy:
2NO₂(g) → N₂(g) + 2O₂(g) with
(\Delta H = -66, \text{kJ mol}^{-1}).
This means that forming 2 moles of (NO₂(g)) releases 66 kJ of energy, hence it takes 66 kJ energy to break it down into products.
For the given reaction, we are forming 1 mole of (NO₂(g)), which corresponds to half of the enthalpy of the provided reaction. Therefore, we will divide the enthalpy change by 2:
(\Delta H = \frac{-66}{2} = -33, \text{kJ mol}^{-1}).
Therefore, the answer is option B: -33 kJ mol⁻¹.