Question

Why are highly substituted alkenes more stable?

Answer 1

More substituted alkenes are more stable than less substituted ones due to hyperconjugation. They have a lower heat of hydrogenation. ... In disubstituted alkenes, trans isomers are more stable than cis isomers due to steric hindrance. 

Answer 2

More substituted alkenes are more stable than less substituted ones due to hyperconjugation. They have a lower heat of hydrogenation. The following illustrates stability of alkenes with various substituents: In disubstituted alkenes, trans isomers are more stable than cis isomers due to steric hindrance