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Old Feb 9th 2018, 09:06 PM   #1
PrincessPeach
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Smile Thermochemical equations

Hi,

The combustion of 2.15g of methanol was found to yield 71.5kJ of heat.
Calculate the deltaH value for this value, and write the thermochemical equation.
This is what I have done so far:
2CH3OH(l) + 3O2 --> 2CO2(g) +4H2O(g)
n(CH3OH) = m/M = 3.15/32.04 = 0.098 mol
So 0.098 mol produces 71.5kJ of energy
1 mol produces 71.5kJ/0.098mol = 729.59 kJ?
So deltaH should be -729.59kJmol-1??
But the answer is −1.45103kJmol−1

Can someone help me clarify where I have gone wrong?
THANK YOU
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