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chemistry question, please help

Discussion in 'MCAT: Medical College Admissions Test' started by lookleft, Apr 5, 2004.

  1. lookleft

    lookleft Member
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    In CO2 is the carbon sp or sp2. I think in TPR they say it is sp, but I thought you have to have a triple bond to be sp3 unless the double bond counts twice.

    Also what is the difference between the geometery and the shape of a molecule. Does one depend on the number of atoms bonded and the other depend on the number of electorns.

    Finally do electron pairs cause the angles to be smaller than predicted without electrons. For example a molecule that has three atoms bonded to it would be trigonal planar and 120 degrees but if it had an electorn pair like NH3 how does this effect the angle.

    Thanks, good luck studying
     
  2. CanIMakeIt

    CanIMakeIt Fellow
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  3. fun8stuff

    fun8stuff *hiding from patients*
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    EPG or Electron Pair Geometry refers to the general configuration. Shape refers to the specific Shape. Some times they are the same, but other times they are different. In CO2 they are the same.

    In H20 the EPG is tetrahedral, the shape is bent. It's general configuration is tetrahedral with 109.5 bond angles (actually slightly less) and it's actual shape is bent.

    You can also get bent from trigonal planar where the bond angles would be slightly less than 120 degrees.
     
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