9. A certain iron-oxygen mineral crystallizes in the spinel structure, which is a fama centered cubic array of oxide ions with three Iron atoms within the unit cell. What is the formula for this mineral? 10. Considering the phase diagram below: 100.0 10.0 Pressure, at 10 0.1 50 200 Temperature, "C a. At what temperature are all three phases present? b. Can a liquid exist at 210 °C? c. What happens to the temperature, pressure and state going from A to C? d. What will happen if the pressure is increased at point ? e. At what temperature would this substance boil at 10.0 atm? 11. Which statement is false? a. Molecular solids generally have lower melting points than covalent solids. b. Metallic solids exhibit a wide range of melting points because metallic bonds cover a wide range of bond strength. C. The metallic solid can be viewed as positive ions closely packed in a sea of valence electrons. d. Most molecular solids melt at lower temperatures than metallic solids. e. The interactions among the molecules in molecular solids are generally stronger than those among the particles that define either covalent or lonic crystal lattices. 12. Which of the following sulfides would be expected to have the lowest melting point? Why? CS2 K25 H2S ScS Cas 13. A metal (MM = 134) crystallizes in a body centered cubic arrangement. What is its density, in g/cm, if the edge of the cubic cell measures 413 pm?