Why is it that big hydrocarbons like in petrol dissolve polystyrene cups where as the little molecules in lighter fuel, don't?

 

p.s. yes I am being very careful with this.

Why is it that big hydrocarbons like in petrol dissolve polystyrene cups where as the little molecules in lighter fuel' date=' don't?

 

p.s. yes I am being very careful with this.

 

It must be something to do with the structure, both are non-polar so thats a good start, as for exactly why I have no idea sorry

 

Maybe this can help you: http://en.wikipedia.org/wiki/Solvation

 

Cheers,

 

Ryan Jones

IIRC (and I hope to be corrected if I`m wrong at all), the petrol breaks down the POLY bit only (it has more free atractors to grab with), you`re then left with monomer Styrene that Can be "attackes" or at least dissolved in, smaller chain molecules such as Ethanol.

the key here is the POLY bit.

Expanded Polystyrene is largely air, the Poly bit makes the molecules stick together as a Polystyrene, when the POLY making bondas are broken the monomer exists as just Styrene.

that is soluable, but you need to break the bonds to get to the monomer 1`st

 

in actual fact, Polystryrene does contain some of the monomer un polymerised and booze can indeed dissolve this! it`s never a good idea to drink alc from a polystyrene cup!