Question

choose hardness thermal conductivity or solubility in water and explain how the property relates to the molecular structure of one of the solid you tested

Answer 1

I’ll choose solubility in water and explain it for sodium chloride (table salt), a common solid in lab tests.

- Structure: NaCl is an ionic solid with a regular crystal lattice (each Na+ surrounded by six Cl− and vice versa). The lattice is held together by strong Coulombic attractions between oppositely charged ions (high lattice energy).
- How water interacts: Water is a polar molecule (partial negative on O, partial positive on H). When NaCl is put in water, water molecules surround (solvate/hydrate) the ions: oxygens point toward Na+ and hydrogens toward Cl−. These ion–dipole interactions release hydration energy.
- Why it dissolves: Dissolution occurs if the hydration energy gained by separating and solvating the ions is enough to compensate for the energy required to break the ionic lattice. Because water has a high dielectric constant and forms strong ion–dipole interactions, it lowers the effective attraction between Na+ and Cl− and stabilizes free ions in solution, so NaCl is quite soluble.
- Key molecular points that control solubility: magnitude of ionic charges and sizes (smaller/higher charge → stronger lattice, less soluble), and the solvent’s polarity/dielectric constant (more polar → better solvation). NaCl’s single charges and water’s strong polarity make dissolution favorable.

If you tested a different solid, tell me which one and I’ll explain that property for it.