So the combustion of butane is written as follows
C8H18 + 12.5O2---%26gt;8CO2 + 9H2O
but since we dont want fractions, we multiple each of the coefficients by 2.
When we are looking for the Heat of Reaction the coefficients do effect the total Heat of reaction.
My question is since we multiplied the reaction by 2 to fix the coefficients.
Do we divide the heat of reaction by 2 to get the %26quot;true%26quot; answer?If we multiply the coefficients in a chemical equation by a factor to remove fractions does the delta H changefor any reaction there is a unique set of integer stoichiometric coefficients, which are the smallest possible values without any of the coefficients being fractional. heats of reaction (or heats of formation, or entropy changes, etc) are defined with respect to this set of coefficients.
so unless stated otherwise, the heat of formation would apply to the reaction that you got _after_ multiplying by 2.
