1. Physical Properties of Covalent Substances Volatility Solubility Electrical Conductivity

2. Volatility – melting and boiling points Many simple covalent substances that are made up of small molecules are liquids or gases at room temperature They have low melting points and low boiling points. Those that are liquids are volatile (i.e.: they evaporate easily)

3. Volatility – melting and boiling points H H H H H H H H H H H H This occurs as the forces between molecules are weak compared to the covalent bonds within the molecules. Very little heat energy is needed to overcome the intermolecular forces (Aka: Van Der Waals Forces)

4. Solubility Most covalent molecules are insoluble in water and soluble in organic solutions. Exceptions: chlorine, hydrogen chloride, alcohol and sugar are covalent substances that are soluble in water.

5. Solubility Most covalent molecules are insoluble in water and soluble in organic solutions. Exceptions: chlorine, hydrogen chloride, alcohol and sugar are covalent substances that are soluble in water.

6. Electrical Conductivity Most covalent elements or compounds do not conduct electricity whether in solid, liquid or gaseous state. As they do not have free-moving ions or electrons to conduct electricity Exceptions: –Carbon (in form of graphite) –Hydrogen Chloride, Sulfur Dioxide, Ammonia (react with water)