Lattice Energy vs Energy of Solvation

[Fortyfive]

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Hello,

I ran into this question and it spurred up some confusion for me. Can someone please clarify?

Adding NH4NO3(s) to water lowers its temperature. How can this be explained?

A.) The solvation energy is greater than the lattice energy.
B. ) The solvation energy is less than the lattice energy.
B is the best answer. If the water became cooler after the ammonium nitrate was added, the reaction must have been endothermic and was driven by the increase in entropy associated with dissolving salt into water. An endothermic reaction means that the bonds broken during the reaction are of higher energy than the bonds formed, which in turn means that the lattice energy (from the bonds broken) is higher than the solvation energy (from the bonds formed).The best answer is B.
C. ) NH4NO3(s) dissolves but does not dissociate into water.
D.) NH4NO3(s) dissociates but does not dissolve into water.

I understand that the since the water is getting cooler, the reaction has to be endothermic. The answer explanation states the bonds formed are of lower energy than the bonds broken. But, I thought that since energy is being required by the reaction, the products would be at a higher energy? 0.o

 

[Cawolf]

The products are at a higher energy.

The water should be viewed as the surroundings, where the heat is drawn from that goes into the products.

 

[Fortyfive]

The products are at a higher energy.

The water should be viewed as the surroundings, where the heat is drawn from that goes into the products.

Can you tell me if this logic is correct?

A low energy reactant has high energy bonds; a higher energy product has low energy bonds

and vice versa

Thanks

 

[Cawolf]

Yes if compared relative to each other that logic makes sense.

There are many other factors that account for the stability of a compound though. If you isolate the bond contributions, then you are correct though.