Comparing the Enthalpy Changes of Combustion of Different Alcohols

... Comparing the Enthalpy Changes of Combustion of Different Alcohols By Steven Duong Background Information The enthalpy change of the combustion of a fuel depends on two things. First, there is the number of bonds to be broken and made - and that depends on the size of the molecule involved. The ?H?c also depends on the type of bonds involved: e.g. combustion of a) methane and b) methanol a) CH4 + 2O2 CO2 + 2H2O H O=O O=C=O H-O-H O=O H-O-H H C H H b) CH3OH + 11/2O2 CO2 + 2H2O H O=O O=C=O H-O-H O H-O-H H C O - H H From the examples shown above, the products are the same, but the key difference is that methanol already has an O-H bond; one of the bonds to oxygen is already made, unlike with methane, where all the new bonds have been made. The energy released during combustion comes from the making of

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