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Intermolecular Forces & Resulting Relative Properties.

Solubility:

  • The extent to which a solute forms a homogeneous mixture with a solvent\

  • Substances need to be attracted to each other to be able to spread or mix easily.

Vapor Pressure:

  • The gas pressure that exists above a liquid

  • It increases with increasing temperature. The gas particles exist because they are able to move away from the liquid.

Melting Point:

  • The temperature at which a solid turns into a liquid, influenced by the strength of intermolecular forces in the solid. As these forces weaken with increasing temperature, the solid structure breaks down, allowing the substance to flow as a liquid.

  • It requires energy to loosen the rigid intermolecular attraction.

Boiling Point:

  • The temperature at which a liquid turns into a gas, which is also determined by the strength of intermolecular forces. A higher boiling point indicates stronger intermolecular forces, as more energy is needed to overcome these attractions and transition the substance into the gaseous state.

  • It requires energy to completely overcome the intermolecular attraction.

Viscosity:

  • A measurement of the “thickness” of a liquid.

  • A substance can be resistant to flow or flow easily.

Ionic: STRONG

Properties:

  • High melting and boiling points due to strong electrostatic forces between ions.

  • Generally soluble in polar solvents, but insoluble in nonpolar solvents.

  • Conducts electricity when dissolved in water or molten, as ions are free to move. Low volatility, as the strong intermolecular attractions prevent molecules from escaping into the vapor phase.

Covalent Network Solids: STRONG covalent bonding

Properties:

  • Hard and SOLID

  • VERY high melting point

  • Non-conductors

  • Insoluble in common solvents

  • ex) diamond (C), Si, SiO2, SiC

Molecular: weak

Properties:

  • Hard and brittle structure, making them suitable for industrial applications

  • Poor electrical conductivity, as they do not have free-moving electrons

  • Non-polar: low melting points and insoluble in water

  • Polar: High melting point and soluble in water

  • Strong intermolecular forces lead to higher boiling points and greater viscosity.

Metallic:

Properties:

  • Variable melting points

  • Malleable and ductile

  • Good conductors

  • May react with water (depends on the properties)

  • Insoluble in common solvents.