1. The Nature of Solids Chapter 10

2. Solids: Gases = very free to move Liquids = relatively free to move Solids = not very free to move

3. Solids: Solids do not move freely like liquids and gases Rather, they vibrate about fixed points

4. Solids: Do not take the shape or volume of the container They are dense and incompressible

5. Solids and kinetic energy: Increase in average kinetic energy = increase in particle vibration = increase in temperature

6. Melting Point: Mp = Solid turning to liquid Vibrations are strong enough to overcome the intermolecular interactions

7. Freezing Point: Opposite of melting point Liquid turns into a solid because the particles slow down and intermolecular forces are stronger

8. Equilibrium: A solid will melt and freeze at the same temperature This is the point of equilibrium, assuming temperature is remaining constant

9. Solids: Ionic Solids (ex: NaCl) = high melting points They have relatively strong forces holding them together

10. This is table salt

11. Solids: Molecular compounds = low melting temperatures Example – hydrogen chloride has a melting temperature of -112 0 C

12. Solids: Not all solids melt, some will decompose Example: wood, cane sugar

13. Sugar or Rock Candy MMMMMM

14. Crystal structure: Crystalline (crystals) = atoms, ions or molecules are arranged in a repeated, three dimensional pattern called a crystal lattice

15. Crystals:

16. Diamond Structure

17. Crystals: Have regular shape Shape reflects the arrangement of the particles within the solid Types of bonds determines the melting point Ionic = high melting point Molecular = low melting point

18. Graphite Structure

19. Crystals: Have sides or faces Angles of the sides for a given crystal are always the same

21. Crystal Classification: Galena –Cubic

22. Crystal Classification: Zircon –Tetragonal

23. Crystal Classification: Blue Topaz –Orthorhombic

24. Crystal Classification: Gypsum –Monoclinic

25. Crystal Classification: Amazonite –Triclinic

26. Crystal Classification: Tourmaline –Hexagonal

27. Crystal Classification: Calcite –Rhombohedral

28. Shape of Crystals: Shape depends on arrangement of crystals Unit cell = smallest group of particles that retains geometric shape

29. More than one Form? Carbon is an example of a crystal that can exist in more than one form

30. Many forms of carbon: Diamonds Graphite Buckyball or Buckminsterfullerene- 60 + carbon atoms shaped like a soccer ball

32. Many forms of Carbon: Allotropes –Two or more molecular forms of the same element in the same physical state (diamond, graphite & buckyballs)

33. Example: diamonds and graphite

34. Amorphous Solids: Lack ordered internal structure Non- crystalline Example- rubber, plastics, asphalt and glasses –Glasses are sometimes called super cooled liquids

35. Nature of Liquids Now, go on to the Nature of Liquids Power Point Click Here Click Here to go to go to Nature of Liquids Nature of Liquids