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Published byEarl Robinson Modified over 9 years ago
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Intermolecular Forces By Peter Demkowicz
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Why? Intermolecular Forces
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In simple, forces with which molecules attract each other.
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Intermolecular Forces Properties Solids/Liquids Boiling/Melting Point Surface Tension Capillary Action Vapor Pressure Miscibility
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Intermolecular Forces Hydrogen Bonds Dipole-Dipole interactions London Dispersion
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Dipole-Dipole Molecules can have a separation of charge Molecules are attracted to each other in a compound by the valence electrons: Positive & Negative Stronger than London Dispersion
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Orientation of Polar Molecules in a Solid
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Dipole A polar molecule that has two poles.
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Hydrogen Bonding Hydrogen bonding is the attraction between a hydrogen atom of a molecule to an unshared pair of electrons in another molecule. Hydrogen bonding occurs in molecules where hydrogen is covalently bonded to a very electronegative element. Hydrogen bonding occurs in molecules containing N, O, F.
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Hydrogen Bonding, Continued Hydrogen bonds are the strongest of all intermolecular forces. Hydrogen bonds are responsible for the physical properties of many biological substances and, more importantly, water.
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Hydrogen Interactions
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Which of these are Hydrogen Bonds? H20 CH3F N2 H2CO
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London Dispersion London forces are named after Fritz London (also called van der Waal forces) London forces are due to small dipoles that exist in non-polar molecules Since electrons are moving around in atoms there will be instants when the charge around an atom is not symmetrical The resulting tiny dipoles cause attractions between atoms/molecules
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(London) Van der Waals Forces Dispersion (continued) Increase as the number of electrons increases. Weakest of all intermolecular forces.
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Put the bonds in strongest order Ionic/covalent Dipole-Dipole London Dispersion Hydrogen Bonding
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Which ones are Dipole, London Dispersion, and Hydrogen Bonding? C2H6 HCl CH3OH H2 H2O
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