Organic Chem TYS questions

• anpanman

  25 May 09, 20:08

  1. I have this particular query to ask of you guys.

  Firstly, why is the structure below considered an alkene with the molecular formula C4H8?

  

  Though alkene is supposed to have C=C double bond? Anyway, this is one of the options chosen in the answer. Thanks all.

• dkcx

  25 May 09, 20:20

  This structure is a cycloalkane or more accurately cyclobutane. Even though this has the same general formula as an alkene, this is not an alkene.

  Did the answer say that this is an alkene?

• anpanman

  25 May 09, 20:22

  Yea. The question asked "Which structures represent alkenes with the molecular structure C4H8?"

   

  This was included in the answer scheme.

• anpanman

  25 May 09, 20:23

  2. Can someone tell me why this is considered an addition reaction

  nC2H4 ---> --------(CH2-------CH2)--------n

• dkcx

  25 May 09, 20:33

  1) I will never consider a cycloalkane an alkene since they have very different chemical reactions but a cyclobutane is very strain and does break easily and react. Unless all the other choices in the question don't even have the alkene general formula, i will never take that as the answer.

  2) It is consider an additional reaction since each molecule is added together to form a chain by the breaking of the double bond, there is no additional product formed through this reaction.

   

• UltimaOnline

  25 May 09, 21:52
• dkcx is right. A cycloalkane is certainly not an alkene, even at 'O' levels (where much is oversimplified). The so-called answer (and/or question) is erroneous. You'd definitely be penalized if you say that compound is an alkene, even at 'O' levels.