Stability of Small Rings

We can use an instrument called a calorimeter to determine how much potential energy is stored in molecules. 

Factors that Affect Alkane Stability

Strain is a super general word. So now let’s go more into specifics of the types of strain you need to recognize. 

Types of Strain

  1. Angle Strain

The ideal bond angle for sp3 hybirdized carbon is 109.5°, so the more we deviate from that number, the more unstable the angle will be! (Aka cyclopropane sucks). 

  1. Torsional Strain

Torsional strain increases with the number of eclipsing hydrogens in a molecule. Some of these rings are so small they can’t twist to prevent these interactions, which makes them unstable.  

Example: Which of the following conformations of cyclohexane would have the lowest heat of combustion?

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