Which solid will be more soluble in water, the one with the larger lattice energy or the one with the smaller lattice energy? assume that solute-solvent interactions are the same for both solids?

Lattice energy is the amount of energy expelled when the solid is disintegrated into ions. For example, the solid is Sodium Chloride. In ionic form, that would consist of sodium and chlorine ions.The solid with a smaller lattice energy would be easily disrupted, hence, when a solvent is incorporated, the solid becomes solvated ions.

Talc (french chalk) is the ingredient