Module 10 Assignment:

• 1) The group 4 elements have these boiling points when bound to four hydrogens: CH4: -162 °C, SiH4: -112 °C, GeH4: -88 °C, SnH4: -52 ° Explain this increasing trend using your knowledge of intermolecular forces.
• 2) Which member of the each of the following pairs would you expect to have a higher boiling point, and why?
  1. O2 and Br2
  2. NO2 and CO2
  3. HF and HCl
• 3) In climates with cold winters, water pipes have to be taken care of carefully in the winter, especially outside water pipes. Explain why, referencing hydrogen bonds.
• 4) A cup can filled all the way to the brim, and then even past the rim. Explain why the water doesn’t overflow.
• 5) Draw a heating cooling curve for a substance that freezes at -57° C and boils at 125.6° Label each phase of the curve with its appropriate name. Also indicate whether each change is endothermic or exothermic.
• 6) Your friend asks you what temperature you like to use to boil your pasta water. Write out how you would explain the idea of phase change to your friend, and teach them about temperature during a phase change.
• 7) Explain each type of crystal and give an example of each:
  1. Covalent crystal
  2. Ionic crystal
  3. Metallic solid
  4. Molecular solid
• 8) What is an amorphous solid? How is it different from a crystalline solid?
• 9) Rank these attraction forces in order from weakest to strongest:
  1. Dipole-dipole
  2. London forces
  3. Hydrogen bonds
  4. Ionic bond
  5. Polar covalent bond
  6. Non-polar covalent bond
• 10) Wax is a solid at room temperature. Water is a liquid at room temperature.
  1. Name the intermolecular forces in each of these substances.
  2. Why is wax a solid at room temperature, while water is a liquid?
     1. One hint- think about size of the molecules involved.