A-LevelChemistryChemical energeticsFeb/Mar 2018Paper 1 Q91 Mark
Hess' Law and bond energy data can be used to calculate the enthalpy change of a reaction. Bromoethane, CH₃CH₂Br, can be made by reacting ethene with hydrogen bromide. CH₂=CH₂ + HBr → CH₃CH₂Br What is the enthalpy change for this reaction?
A–674 kJ mol⁻¹
B–64 kJ mol⁻¹
C+186 kJ mol⁻¹
D+346 kJ mol⁻¹
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The correct answer is B. This question tests the candidate's understanding of chemical energetics within the Chemistrysyllabus. The examiner's mark scheme requires...
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Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
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