12. Solubility of different compounds - Polar Solvents

What is the pattern of solubility of molecules determined by?

Type of intermolecular force (VDW or hydrogen)

What is the general rule for solubility of different compounds?

Polar substances (hydrogen bonds) will dissolve other substances that have charge / are polar. Non polar substances (VDW) will dissolve other non polar substances

Draw dipole diagram of water

Yes

What happen when sodium chloride dissolves?

Aqueous sodium ions and aqueous chloride ions are formed

Show the ionic equation for sodium chloride dissolving?

NaCl(s) → Na⁺(aq) + Cl⁻(aq)

What 2 processes can dissolving be considered?

1) Breaking electrostatic attraction between ions in ionic lattice 2) Forming aqueous ions with attractive forces being established between water molecules and these ions

What happens to ions after being separated?

Prevented from reforming crystal lattice because each ion is surrounded by water molecules -> hydrated

Draw hydrated sodium ion

Yes

Draw hydrated chlorine ion

Yes

Why is sodium chloride soluble in water?

Hydration energy released as water molecules bind to ions -> This is enough to compensate for energy needed to overcome ionic bonding between ions

Why are some salts like BaSO₄ insoluble?

Hydration energy not great enough to overcome energy required to break ionic bond (lattice energy)

Describe ethanol

Also polar so can interact with polar water molecules by forming new hydrogen bonds between ethanol and water molecules

Draw diagram to show how ethanol dissolves water?

Yes