Given $DeltaH_"combustion"^@$ for butane is $-2657kJmol^-1$ , what is $"heat of combustion"$ for butane in $J*g^-1$ ?

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Answer 1 · 2017-03-22T16:39:53

$"Heat of combustion of butane"$ $-=$ $45.7xx10^3*J*g^-1$

We have data for the stoichiometric equation:

$C_4H_10(g)+ 13/2O_2(g)rarr 4CO_2 + 5H_2O$ $DeltaH_"rxn"=-2657*kJ*mol^-1$

Note that I halved the equation because it makes the arithmetic a little bit easier. I also had to halve the enthalpy change accordingly.

And thus $"Heat of combustion of butane"$ $-=$ $(-2657xx10^3*kJ*cancel(mol^-1))/(58.12*g*cancel(mol^-1))=45.7*kJ*g^-1$ .

Given DeltaH_"combustion"^@DeltaH_"combustion"^@ for butane is -2657*kJ*mol^-1-2657*kJ*mol^-1, what is "heat of combustion""heat of combustion" for butane in J*g^-1J*g^-1?