# quick AS chemistry unit 2 questionWatch

#1
I know this one is really simple, but I don't understand why I don't understand it!!

Burning 1.00g of octane gives 48.4KJ of energy. Calculate the heat energy produced by burning 1.00g of methane.

thanks
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13 years ago
#2
Mr of Octane = 106
Mr of Methane = 16

1.00g of Octane -----> 48.4kJ
1.00g of Methane -----> 3.0kJ
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#3
that's what I worked it out to be, but the mark scheme says 55.6KJ
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#4
anyone else?
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13 years ago
#5
You sure you posted the correct question? Either that or the mark scheme is wrong. I can't see how combustion of a compound with a smaller number of carbon and hydrogen atoms can produce more heat.
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13 years ago
#6
(Original post by gordon2002)
I know this one is really simple, but I don't understand why I don't understand it!!

Burning 1.00g of octane gives 48.4KJ of energy. Calculate the heat energy produced by burning 1.00g of methane.

thanks
don't suppose they gave you any bond energies?
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13 years ago
#7
(Original post by gordon2002)
I know this one is really simple, but I don't understand why I don't understand it!!

Burning 1.00g of octane gives 48.4KJ of energy. Calculate the heat energy produced by burning 1.00g of methane.

thanks
any bond energies?
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#8
(Original post by hungry_hog)
don't suppose they gave you any bond energies?
nope
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#9
(Original post by Widowmaker)
any bond energies?
nope
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#10
it was an edexcel past question from about 7 years ago
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13 years ago
#11
I don't think that we're expected to be able answer such question without bond energies. Probably part of the old specifications.
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#12
(Original post by mizfissy815)
I don't think that we're expected to be able answer such question without bond energies. Probably part of the old specifications.
yeah, it is the old spec.
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