C2.3.2 Properties of Simple Molecular Substances

• Weak intermolecular forces are stronger than covalent bonds

  False
• Simple molecular substances have low melting and boiling points due to weak intermolecular forces
• Simple molecular substances do not conduct electricity because they lack free-moving electrons
• Steps involved in the formation of van der Waals forces:

  1️⃣ Temporary fluctuations in electron distribution

  2️⃣ Creation of temporary dipoles

  3️⃣ Attraction between neighboring molecules
• Simple molecular substances have low melting and boiling points because of weak intermolecular forces
• Examples of simple molecular substances include water, carbon dioxide, and methane
• Hydrogen bonds are stronger than van der Waals forces


  True
• Steps involved in the formation of hydrogen bonds:

  1️⃣ Hydrogen atoms bond to highly electronegative atoms

  2️⃣ Strong dipole-dipole attraction forms
• The strength of hydrogen bonds depends on the number of hydrogen bonds formed


  True
• Weak intermolecular forces include van der Waals forces and hydrogen bonds.
• Hydrogen bonds occur when hydrogen atoms are bonded to electronegative atoms like oxygen or nitrogen.
• Match the type of intermolecular force with its key factors:

  Van der Waals ↔️ Molecule size

  Hydrogen Bonds ↔️ Number of hydrogen bonds
• Polar molecules form stronger intermolecular interactions.
• Match the substance with its physical state at room temperature:

  Water ↔️ Liquid

  Carbon dioxide ↔️ Gas
• Simple molecular substances have low melting and boiling points.
• The weak intermolecular forces in simple molecular substances require little energy to overcome, resulting in low melting and boiling points.


  True
• Match the substance with its solubility in water:

  Water ↔️ Highly soluble

  Methane ↔️ Insoluble

  Ethanol ↔️ Soluble
• Simple molecular substances are held together by weak intermolecular forces.
• Weak intermolecular forces are attractive forces between molecules that are weaker than covalent or ionic bonds
• Hydrogen bonds are stronger than van der Waals forces.


  True
• Hydrogen bonds occur when hydrogen atoms are bonded to highly electronegative atoms like oxygen or nitrogen
• How does the size of a molecule affect van der Waals forces?

  Larger molecules increase forces
• Match the type of intermolecular force with its strength and key factors:

  Van der Waals ↔️ Weak, Molecule size

  Hydrogen Bonds ↔️ Stronger, Number of hydrogen bonds
• Water is a simple molecular substance that is a liquid at room temperature due to its strong hydrogen bonds
• Why do simple molecular substances have low melting and boiling points?

  Weak intermolecular forces
• Water is highly soluble in water due to its polarity and ability to form hydrogen bonds.


  True
• Simple molecular substances have poor electrical conductivity because they have no free electrons or ions
• Simple molecular substances are held together by weak intermolecular forces such as van der Waals forces and hydrogen bonds
• Simple molecular substances are composed of small molecules
• At room temperature, simple molecular substances can exist in a solid, liquid, or gas
• Simple molecular substances are generally soluble in water

  True
• Match the simple molecular substance with its chemical formula:

  Water ↔️ H2O

  Carbon dioxide ↔️ CO2

  Methane ↔️ CH4

  Ammonia ↔️ NH3
• Simple molecular substances are held together by strong covalent bonds

  False
• Simple molecular substances are good electrical conductors

  False
• Simple molecular substances have similar properties to ionic compounds

  False
• The strength of intermolecular forces increases with the size of molecules
• Intermolecular forces become stronger when molecules are more polar
• Match the type of intermolecular force with its relative strength:

  Van der Waals forces ↔️ Weaker

  Hydrogen bonds ↔️ Stronger
• Van der Waals forces arise from temporary fluctuations in electron distribution.


  True
• Hydrogen bonds are stronger than van der Waals forces.


  True