Question
SECTION 2 (AC2.1/AC2.2) (A) Imagine you have been given a series of materials to react together and the following enthalpy change data has been recorded. Explain the terms exothermic and endothermic, and identify which of the following are exothermic and endothermic reactions. Ensure that you explain your reasoning. Your explanation should be a maximum of 500 words. 1. N₂ + 20₂ → 2NO₂ AH = +68kJ mol-¹ 2. C3H8 +502 → 3CO2 + 4H₂O AH = -2220kJ mol-¹ AH = -486.3kJ mol-¹ AH = +566kJ mol-¹ 3. 2H₂ + O2 → 2H₂O 4. 2CO₂ → 2CO + + O₂ (B) You have been asked to calculate the enthalpy change in the following reaction: 2Al(s) + Fe2O3(S) → Al2O3(s) + 2Fe(s) The reaction occurs in the following stages: Chemical Change Assignment 1. 2Al(s) + Fe2O3(S) → Al2O3(s) + 2Fe(1) 2. Al₂O3(s) + 2Fe(1)→ Al2O3(s) + 2Fe(s) 3. Al2O3(s) + 2Fe(1)→ Al2O3(s) + 2Fe(s) Note stages 2 and 3 look the same, but the reaction is cooling from 1700°C to 25°C and hence the enthalpy change there. Calculate the overall enthalpy change for the reaction. You must show your workings within your submission, and explain your reasoning. Your explanation should be a maximum of 300 words. AH = -732.5kJ mol-¹ AH = -27.6kJ mol-¹ AH = -91kJ mol-¹ 1
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