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Energetics Ambiguity

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Hey guys!

I was reading through my textbook today and I found a worked example that got me very confused...

What mass of propanol must be burnt in excess air to produce 10000 kJ of energy according to the following thermochemical equation?

2C3H7OH + 9O2 ---> 6CO2 + 8H2O deltaH = -4034 kJ/mol

So this seems simple enough. But the worked solution states:

From the equation, 2 mol of propanol yields 4034kJ of energy, so x mol of propanol yields 10000kJ of energy.

WAIT WAIT WAIT. the deltaH value states -4034 kJ PER MOL. then why does 2 mol of propanol yields 4034 kJ of energy? Shouldn't it yield 8068 kJ of energy intead?

I think I must be wrong because that example originated from a standard textbook. However, I do not understand why the solution in the textbook is correct. Please feel free to enlighten me.

Thanks in advance :D

Edited by MistyRose

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