CK-12-Chemistry Intermediate

http://www.ck12.org Chapter 13. States of Matter

Lesson Review Questions

Reviewing Concepts

1. How are the particles arranged in most solids?


2. Describe what happens when a solid is heated to its melting point. What phases are in equilibrium at the
   melting point?


3. Wet clothes can be hung on a clothesline in sub-freezing temperatures, and they will still dry. Explain.


4. What accounts for the differences between the seven basic crystal systems?


5. Explain the difference between a crystal lattice and a unit cell.


6. What are three kinds of unit cells that would be classified as having a cubic crystal system?

Problems

7. Use the table above (Table13.2) to identify which crystal system or systems fit the following criteria.
   a. The lengths of all edges are the same.
   b. All angles between faces are 90°.
   c. No faces intersect at 90° angles, and no two edges are the same length.


8. From the given descriptions, identify each of the following as an ionic crystal, a metallic crystal, a covalent
   network crystal, or a molecular crystal.
   a. Substance A melts at 125°C and does not conduct electricity as either a solid or a liquid.
   b. Substance B is very hard and melts at 3440°C. It does not conduct electricity either as a solid or a liquid.
   c. Substance C is hard and brittle and melts at 1720°C. It does not conduct electricity as a solid, but it does
   conduct as a liquid.
   d. Substance D is malleable and conducts electricity well as a solid. It melts at 1135°C.


9. Identify whether the solid form of each of the following substances is an ionic crystal, a metallic crystal, a
   covalent network crystal, or a molecular crystal.
   a. Mn
   b. MgBr 2
   c. Xe
   d. NH 4 Cl
   e. CO 2
   f. As
   g. Pd
   h. SiC


10. Use the figure above (Figure13.16) to list the three kinds of cubic unit cells in order from least densely
    packed to most densely packed.

Further Reading / Supplemental Links

• TheSolidState, (http://www.wisc-online.com/objects/ViewObject.aspx?ID=GCH6904)


• CrystallographyofGemstones:TheCrystalSystem, (http://www.allaboutgemstones.com/crystalline_structu
  res.html)


• Lesley E. Smart; Elaine A. Moore,Solid State Chemistry: An Introduction (3rd edition). CRC Press, 2005.


• Donald E. Sands,Introduction to Crystallography, Dover Publications, 1994.