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Factors that affect the strength of London Forces1) The more protons and electrons in a molecule, the stronger the London Forces

-(higher molar mass usually means stronger London Forces)

2) A molecule with a linear shape will have stronger London Forces than a molecule with a spherical shape (if p+ and e- are the same)

What type of IMF are in the following molecules?

CH3OH CH3Cl

CBr4 CI4

H2 H2O

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Other Properties Affected by Intermolecular Forces:

Surface Tension:(The attraction of molecules to each other on a liquid's surface)Relationship:

Volatility of Liquids: (How easily they evaporate)Relationship:

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Viscosity of Liquids: (Their resistance to flow)Relationship:

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Ionic Compounds do not have intermolecular forces• When you melt an ionic compound you are breaking the attractive forces between ions

Comparing the Strength of Intermolecular and Intramolecular Forces

Ionic Bond Covalent Bond Hydrogen Bond

London Forces

Dipole Dipole Forces

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page 69 - 5-7

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3) methane is polar so it has dipole forces while methane is non-polar so it has London forces only. Dipole forces are stronger than London forces so it takes more energy to separate the molecules (which is what happens when something boils4) The stronger the intermolecular force the higher the melting and boiling point

5) Test the conductivity of the solid and the solution-the metal will conduct as a solid-the ionic compound will conduct in solution-the molecular compound will never conduct

6) Ionic compounds are hard, so they are hard to shape

Ionic compounds are brittle so they break when force is applied

7)

a) The compound appears to be molecular so it should have a low melting point

b) The atoms are connected by covalent bonds

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