Question

An isomer with a straight chain structure will require:
more energy to melt than the straight chain structure

a higher temperature to boil than the straight chain structure

less energy to melt than the branched structure

the same energy to boil as the straight chain structure

Answer 1

I dont understand the question. You are comparing straight chain with straight chain? Or did you mean to write branched vs straight chain isomers?.

If so i know that straight chain isomers have greater surface areas than branched chain isomers. That would mean a branched chain hydrocarbon would require less energy to melt/boil than its straight chain isomer. Since a smaller surface area reduces IMFs and therefore mp/bp.

Hope that helps.