Exam 3 Material:
Supplemental Instruction
Iowa State University / Leader: / Emily and Max
Course: / Chem 167
Instructor: / Bonnacorsi and Burnett
Date: / 12/14/14
  1. Draw the Lewis structures for the following molecules. Determine the shape, bond angles, hybridization of the central atom, polarity of the molecule, and how many sigma and pi bonds are present. (There are exceptions to the octet rule.)
  2. FNO
  3. HCO2 -
  4. ICl5
  5. H2NCN
  6. TeCl4
  7. C2F4
  8. SNF3
  9. Barium crystallizes with an edge length of 5.025 x 10-8 cm in a body-centered cubic unit cell. What is the density of barium?
  10. Explain using a diagram how doping will increase the conductivity of a semiconductor. Arsenic would be which type of doping for germanium?
  11. Identify the kinds of IMF (London dispersion, dipole-dipole, or hydrogen bonding) that are the most important in each of the following substances.
  12. Methane, CH4
  13. Methanol, CH3OH
  14. Chloroform, CHCl3
  15. Benzene, C6H6
  16. Ammonia, NH3
  17. Sulfur dioxide, SO2
  18. Referring to number 5, which molecule has the highest boiling point, highest vapor pressure, and lowest surface tension?
  19. Which of the following is an example of an alternating copolymer?
  20. ABABABABABABABABAB
  21. AABAAABBBAAABAABAB
  22. AAABBBAAABBBAAABBB
  23. BBAAAAAABBBABBBBAA
  24. Which of the following statements about polymers is false?
  25. Addition polymers begin with the formation of a free radical.
  26. The degree of polymerization is defined as (molar mass of the polymer)/(molar mass of the monomer).
  27. HDPE and polystyrene are examples of condensation polymers.
  28. A small molecule such as water is eliminated during a condensation reaction.
  29. Creating copolymers or graft polymers is a very useful way to engineer specific properties in the polymer.
  30. A 1.000 g sample of octane (C8H18) is burned in a bomb calorimeter containing 1200 grams of water at an initial temperature of 25.00ºC. After the reaction, the final temperature of the water is 33.20ºC. The heat capacity of the calorimeter is 837 J/ºC. The specific heat of water is 4.184 J/g ºC. Calculate the heat of combustion of octane in kJ/mol.

ΔH°f
B2H6(g) / 36.0 kJ/mol
H2O(g) / -241.8 kJ/mol
B2O3(s) / -1273.4 kJ/mol

9.  Calculate the heat of combustion of diborane:

  1. Calculate the ΔH°rxn for: 2 H2O(l) à 2 H2(g) + O2(g)

H2O(l) à H2O (g) ΔH° = 44.01 kJ

2 H2(g) + O2(g) à 2 H2O(g) ΔH° = -483.64 kJ

11.  Given the thermochemical equation:

N2(g) +O2(g) →2 NO(g) ΔH=180.6 kJ

If 558 kJ of energy are supplied, what mass of NO can be made?

  1. Which of the following is true about thermodynamics?
  2. If ΔG for a reaction is positive, the reaction will occur spontaneously.
  3. If ΔH and ΔS are both negative, the process will be spontaneous at high temperatures.
  4. The entropy of the universe is always decreasing.
  5. If the process is spontaneous, the entropy must be positive.
  6. All of the above are false.
  7. When 0.0157 kg of a compound with a heat of combustion of -37.6 kJ/mol is burned in a calorimeter, 18.5 kJ of heat are released. What is the molar mass of the compound?