Ch 7

• Liquids and solids are much more dense than gases
• Most organic liquids and solids have densitites from 0.7 to 2.0 g/cm^3
• Liquids conform to the shape of the container
• Solids maintain their shape without any container
• Liquids and solids have significant attractive forces
• Based on Coulomb's Law, decreasing distance increases attractive force
• Decreasing temperature or increasing pressure of a gas will help it condense to a liquid
• The boiling point of a gas is also known as the condensation point
• Low boiling points indicate low attractive forces
• High boiling points indicate higher attractive forces
• Polarizability refers to the ease with which the electron cloud around an atom or molecule can be deformed into a dipole
• Small atoms that hold electrons tightly near the nucleus have a low polarizability
• Large atoms with many loosely held electrons have a high polarizability
• Polarizability explains why halogens have much higher boiling points than noble gases
• Normal alkanes refers to the series of compounds with C and H
• The formula for a n-alkane is $CnH(2n+2)$
• The more electrons in a molecule, the more opportunity there is to form instantenous dipoles
• Homologous series are a series of compounds where their formulas vary in a specific pattern
• Due to its network structure, water has the greatest increase in boiling point
• Solids have the property of retaining their shapes with or without a container

  
• Solids have rigid crystal structures

  
• Phase changes are represented by heating or cooling cures and the phase diagram
• The heat capacity is the reciprocal of the slope of the curve in regions where temperature increases a heat is added
• The specific heat capacity is the heat capacity divided by the number of grams of sample used
• Temperature does not change during phase changes
• Super heating occurs when the temperature of a liquid exceeds the boiling point
• The molar heat of fusion is for melting
• The molar heat of vaporization is for vaporization
• The cooling curve is the reverse of the heating curve
• Condensation point = boiling point
• Crystallization point = melting point
• Supercooling occurs when a liquid is cooled to a temperature below its melting point and remains a liquid
• A metastable liquid will crystallize rapidly if sufficiently disturbed or shaken
• Heating curve provides info on: melting point, boiling point, specific heat capacities, heat of fusion, heat of vaporization