The reaction of Problem 13.40 is run in the reverse direction (P → R).

(a) Is it exothermic or endothermic?

(b) Calculate ΔE_rxn.

(c) Is what you just said and calculated for (a) and (b) consistent with the definition of Δ(any quantity) given in Problem 13.41? Explain.

Data from Problem 13.40

A reaction occurs in which 1 mole of A is converted to 1 mole of B. If 1 mole of A has an energy content of 20 kJ and 1 mole of B has an energy content of 60 kJ, is this reaction exothermic or endothermic? Calculate ΔE_rxn.

Data from Problem 13.41

Δ(Any quantity) is always defined as (final value of quantity) – (initial value of quantity). Now consider the quantity ΔE_rxn.

For the forward reaction R → P, is ΔE_rxn = E_Reactants – E_Products? Explain your answer.

According to your answer to (a), what does it mean when ΔE_rxn for a reaction is negative?