Is this reaction endothermic or exothermic?
AB ---> A+B
a. Exothermic, ΔH rxn is positive.
b. Endothermic, Delta ΔH rxn is negative.
c. Endothermic, ΔH rxn is positive.
Exothermic reactions dH is -
Endothermic reactions dH is +
I would expect this reaction to be endothermic since you are breaking the AB bond and not forming bonds on the product side.
To determine whether the reaction is endothermic or exothermic, we need to examine the sign of the enthalpy change (∆H rxn). Endothermic reactions absorb heat from the surroundings, causing the surroundings to cool down, so ∆H rxn is positive. On the other hand, exothermic reactions release heat into the surroundings, causing the surroundings to warm up, so ∆H rxn is negative.
In the given options, we should choose the statement that aligns with the correct sign of ∆H rxn.
Option a states that the reaction is exothermic, but it also claims that ∆H rxn is positive. Since exothermic reactions have negative ∆H rxn, this option contradicts itself.
Option b states that the reaction is endothermic and ∆H rxn is negative. However, this contradicts the fact that endothermic reactions have positive ∆H rxn.
Option c states that the reaction is endothermic and ∆H rxn is positive. This aligns with our understanding that endothermic reactions absorb heat and have positive ∆H rxn.
Therefore, the correct answer is option c.