We have to add the both half cell equations and eliminate the number of electrons lost/gained.
<h3>What modification must Kim make to the equations?</h3>
The term redox reaction is a type of reaction that occurs when an electron is lost or gained in a reaction system. We can see that in this reaction, zinc looses two electron which are gained by copper.
If we want to obtain the equation 4.9 which is the overall equation of the redox reaction from the various half cell equations then we have to add the both half cell equations and eliminate the number of electrons lost/gained.
Learn kore about redox reaction:brainly.com/question/13293425
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Energy diagram for and endothermic and exothermic reaction
The balanced chemical equation for the combustion of butane is:

Δ
= Σ
Δ
-Σ
Δ
=
=[-3148kJ/mol+(-2418.2kJ/mol)]-[(-251.2kJ/mol)+0]
= -5315 kJ/mol
Calculating the enthalpy of combustion per mole of butane:

Therefore the heat of combustion per one mole butane is -2657.5 kJ/mol
Correct answer: -2657.5 kJ/mol