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    hi im stuck on this question
    Which of the following mixtures could not form when octane, C8H18, is cracked?
    A propane + pentene
    B butane + butene
    C pentane + propene
    D heptane + ethene

    the answer says D but i have no idea why. thanks
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    It's easy - octane has 8 carbons, so the products of cracking must have 8 carbons in total.
    Pent + prop = 5 + 3 = 8
    But + but = 4 + 4 = 8
    Obviously C is the same as A but the other way around
    D is the answer because hept + eth = 7 + 2 = 9


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    7 + 2 = 9

    This could only occur from nonane, not octane, as octane has 8 carbons.

    Just realised this is the exact same answer as RavenclawRiver's. Sorry!
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    oh right i see, cheers guys, wat got me was the cracking bit, i thought they were supposed to be split up?
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    Yeah, the octane (or nonane in the case of D) is split up into 2 products which are shown in the answers :P


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