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Sodium burns in oxygen giving out heat energy and forming the compound Na2O - CIE - A-Level Chemistry - Question 8 - 2019 - Paper 1
Question 8
Sodium burns in oxygen giving out heat energy and forming the compound Na2O. The equation for this reaction is shown. 2Na(s) + rac{1}{2}O_2(g) → Na_2O(s) Which st... show full transcript
Worked Solution & Example Answer:Sodium burns in oxygen giving out heat energy and forming the compound Na2O - CIE - A-Level Chemistry - Question 8 - 2019 - Paper 1
Step 1
Which statement about the reaction is correct?
Answer
The enthalpy change for the formation of sodium oxide, represented in the equation, corresponds to the standard enthalpy change of formation, making statement D correct.
To clarify:
- Statement A is incorrect because ΔH° does not equal twice the bond energy of Na-O; it reflects the overall energy change of the reaction.
- Statement B is incorrect as the reaction is exothermic, implying a negative ΔH°.
- Statement C is also incorrect since this equation reflects formation rather than combustion. Therefore, the correct answer is D.