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제목 [Lisa Kim] IB Chemistry HL Part 2
Lesson 5.5_Topic 5_Paper 2 (SL) 16
작성자 kim*** 등록일 2020-07-17 오후 3:37:38

안녕하세요 선생님. 


Topic 5 paper 2 질문이 있어서요. 선생님께서 강의하실 때 칠판에 안 적으시고 말씀만 하셔서 질문에 답을 어떻게 해야할지 잘 모르겠습니다. 


Question #3 cont.

C. The Data Booklet value for the enthalpy of combustion of methanol is -726 kJ mol ^-1. Suggest why this value differs from the values calculated in parts (A) and (B).


이 질문에 답해주시면 감사하겠습니다. 
2020-07-20 오전 12:15:04

 

(c)  

(i)  bond enthalpies are average values/differ(slightly) from one compound to another (depending on the neighbouring atoms) / methanol is liquid not gas in the reaction.

(ii)  notall heat produced transferred to water / heat lostto surroundings/environment / OWTTE / incomplete combustion (of methanol) / water forms as H2O(l) instead of H2O(g).
      Donot allow just “heat lost”.

 
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