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Chapter 10. Bonding (This you should remember from Pre-AP … not that I really expect it. ^.^). Intermolecular Forces. What is the difference between Intramolecular and Intermolecular? Intra is within the molecule ( how the molecule is made), while inter is the bonding between the molecules.
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Chapter 10 Bonding (This you should remember from Pre-AP … not that I really expect it. ^.^)
Intermolecular Forces • What is the difference between Intramolecular and Intermolecular? • Intra is within the molecule ( how the molecule is made), while inter is the bonding between the molecules. • What happens during a phase change? Do the molecules change? • NO!!! The molecules remain intact (intra), while the inter forces change
Directly related to properties such as melting point, boiling point and the energies to overcome the forces of attraction between particles in changes of state (Hfusand Hvap). • Determines solubility of gases, liquids and solids in various solvents. • Energy is required to overcome intermolecular forces in a liquid to make a gas. This energy is the heat of vaporization, Hvap.
Types of Forces • Dipole-Dipole Forces • These are the forces that act between polar molecules. • Orientation wise … Opposites attract (maximum) • 1% as strong as covalent or ionic • Greater the distance between the molecule the weaker the bonds.
Types of Forces Part Dos • Hydrogen Bonding • A strong sort of dipole dipole • Hydrogen pairs up with ONLY nitrogen, oxygen, or fluorine. Recall HNOF! • Two factors of strength • The great and powerful polarity of the bonds • Closeness of the dipoles (due to hydrogen's small size).
Types of Forces Part 三 • London Dispersion Forces • These are the forces that occur between every molecule • Temporary dipoles are formed/ induced • Also called Induced Dipole-Dipole • Polarizability- the ease in which the electron loud of an atom can be distorted.
Effects of Forces • Forces affect physical properties… • Smaller size of molecule = higher boiling point (Hydro) • Check out figure 10.4 • Larger the molecule = higher boiling point (others) • Larger the atomic number the higher greater the freezing point (in a family). • Like dissolves like • The more carbons the less soluble the molecule is in a polar solvent.