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This overview explores the various intermolecular attractions such as dispersion forces, dipole interactions, and hydrogen bonding, explaining how these forces influence the properties of liquids and solids. It delves into colligative properties like freezing point depression and boiling point elevation, highlighting the importance of solute concentrations in solutions. Additionally, we discuss the structures of metallic and ionic solids, detailing unit cells and their characteristics. This comprehensive guide provides essential insights for students and enthusiasts interested in chemistry.
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Unit 02 B IMFA, liquids, solids, solutions, colligative properties
Intermolecular Attractions Van Der Walls Forces
Dispersion Forces • Dispersion forces are caused by the movement of electrons • Strength of attraction is determined by quantity of electrons • Example: Halogen family • Chlorine and Fluorine are gases @ STP due to their low number of electrons • Bromine has sufficient electrons to produce a liquid @ STP • Iodine is solid @ STP
Dipole Interactions • Dipole interactions are the attraction betweens the opposite poles of polar molecules • Hydrogen bonds are a especially strong of dipole interaction
Hydrogen Bonding • Hydrogen Bonds, the strongest of the intermolecular forces involves the attraction of molecules through the dipole created by the bond between a Hydrogen and a very electronegative atom
Colligative Properties • The properties of a solution that depend only on the number of solute particles per solvent molecule • Molality = moles of solute/kilogram of solvent
Freezing Point Depression • Freezing point of a solution is lowered with the addition of a solute, usually quite small • ∆Tf =Kfm • ∆Tf = freezing point depression m=molality,Kf=molal freezing point constant
Boiling Point Elevation • Adding a solute to a solution increases the temp. at which it boils • ∆Tb =Kbm
Simple Cubic • 1 net atom per unit cell • Cell edge = 2r
Body Centered Cubic • 2 atom per unit cell • Cell diagonal = 4r = (√3)(Length of Edge)
Face Centered Cubic • 4 net atoms per unit cell • Cell diagonal = (√2)(length of edge)