Suppose reaction A involves the making of bonds and 44.5 J of energy, reaction B involves the making of bonds and 17.3 J of energy, and reaction C involves the breaking of bonds and 12.5 J of energy
What is the overall A + B + C reaction energy? Is this an exothermic or an endothermic reaction? Explain.
In making bonds, the total energy release was 44.5 J + 17.3 J = 61.8 J. This is
more than the energy supplied to break bonds, 12.5 J. Overall in this reaction, bonds are
made and net energy is supplied by the chemical system to the outside. This is an
exothermic reaction, because energy of 49.3 J [= 61.8 J - 12.5 J] can be extracted from the
system when the reaction occurs.
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