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### Topic: Cracking equations  (Read 29049 times)

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#### upsidedown

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##### Cracking equations
« on: May 29, 2008, 04:38:23 PM »
I know when cracking usually an alkane and an alkene is produced, but why when cracking hexane the equation

C6H14 → C3H6 + C3H8

and not C6H14 → C4H8 + C2H6

because both are an alkane and an alkene.

Thanks for any help
« Last Edit: May 29, 2008, 04:51:09 PM by upsidedown »

#### cliverlong

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##### Re: Cracking equations
« Reply #1 on: May 29, 2008, 04:47:12 PM »
I know when cracking usually an alkane and an alkene is produced,
Agreed
Quote
but why when cracking hexane the equation

C6H14 → C3H6 + C3H8

and not C6H14 → C4H8 + C2+H6

because both are an alkane and an alkene.
Is "C2" an alkane or alkene ?

Is "H6"  an alkane or alkene ?

But separately, I have read that cracking produces a "variety" of hydrocarbon (emphasis intended) products . So going back to your first equation

C6H14 → C3H6 + C3H8

I'm not sure that C3H6 + C3H8 will be the only products - which is where you came in.

Now ... going back to what you wrote I guess you made a slight slip and meant

C6H14 → C4H8 + C2H6

which balances OK.

However, it might be the case that the energy of the various paths favour the production of certain products rather than others, or that there might be "rules" that guide where the splitting takes places - but I haven't come across them.

I too will be interested to find out if there is a "definitive" answer to this.

Clive

#### upsidedown

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##### Re: Cracking equations
« Reply #2 on: May 29, 2008, 04:50:29 PM »
Sorry the C2+H6 is a typing mistake, I have corrected it now.