In pairs :1. Build; water, carbon dioxide, Ammonia
2. Draw these molecules in 3D, include bon
dangles and lone pairs.
Must : Describe Van der Waals,
Dipole, and Hydrogen Bonding.
Should : Relate intermolecular force
to physical property.
Could : Imagine 3D shapes of
What are Intermolecular Forces ?
• Attractive forces between neighbouring
Van der Waal’s Forces
• ALL intermolecular forces are Van der Waal’s
• Temporary fluctuating dipoles.
Dipole-Dipole interactions result when two
polar molecules approach each other in
space. When this occurs, the partially
negative portion of one of the polar
molecules is attracted to the partially
positive portion of the second polar
A hydrogen bond is the electromagnetic attractive interaction between polar
molecules in which hydrogen is bound to a highly electronegative atom, such
as nitrogen, oxygen or fluorine.
Why did we do this experiment ?
• Type of IMF determines many things, one of
which is solubility.
• I2(aq) + I−(aq) ⇌ I3−(aq)
• In which solvent was Iodine most soluble ?
• How did the introduction of a polar Iodide
affect the result ?
5 Question Quiz
• Which would have the higher boiling point ? –
Chlorine, or Hydrogen Chloride – Why ?
• Why is water a liquid ?
• Why won’t Sodium Chloride dissolve in
• What is another name for Van der Waals
• What is Darth Vader’s dad called ?
• Use Mr Midgley site here.
• Chem factsheet on bonding issued yesterday.