HTML University

Science Dept.

Chemistry CHE 100 Notes
N. The Solid State

1. General Characteristics
   1. No Expansion (at constant T)

   2. Maintains Shape

   3. Maintains Volume

   4. Compressibility: Practically uncompressible

   5. High density

   6. Mixability: Very slowly except under extreme pressure

2. True vs Amorphous Solids
   1. Crystalline Solid

   2. Amorphous Solid

   3. Polymorphism
      1. The assumpstion of two or more crystal systems by the same substance

      2. Graphite & Diamond

3. Heat of Fusion or Solidification
   1. Freezing Point <====> Melting Point

   2. Heat of Fusion or Solidification
      1. Specific Heat of Fusion of water at 0^oC at 1 STD ATM is 80 cal/g or 3.3 x 10⁵joules/Kg

      2. Molar Heat of Fusion of water at 0^oC at 1 STD ATM is 1.44 Kcal/mole or 6.02 Kj/mole

4. Sublimation - Solid into Vapor
   1. When a solid goes directly into a vapor state
      1. When the vapor pressure of a solid is equal to or greater than the pressure of the vapor of the material above the solid

      2. Ice will sublime at -5^oC when the partial pressure of H₂O in the atmosphere is 3.0 torr or less. (since ice at -5^oC has a vapor pressure of 3.01 Torr)

5. The Three States of Matter
   1. What is the heat, in calories, needed to convert 100g water as ice to 100 g steam?
      1. 100g H₂O x (80 cal/g) = 8000 cal/100g; ice solid to liquid

      2. 100g H₂O x (1 cal/^oCg) x 100^oC = 10,000 cal/100g H₂O; liquid to liquid

      3. 100g H₂O x (540 cal/g steam) = 54,000 cal/100 g H₂O; liquid to steam

      4. Total = 72,000 cal or 72 Kcal