Guided Notes: Chapter 19 sections 4 & 5

Name: ______date: ______due: Mon, 1/31/2011

  1. For elements, what is the value of entropy? ______
  2. Molar entropies of gases are ______than liquids and solids.
  3. Molar entropies generally ______with increasing molar mass of substance.
  4. Molar entropies usually ______with the number of atoms in the formula of the substance.
  5. For example, use Appendix C to solve (sample exercise 19.5): Calculate ΔSo for the synthesis of ammonia (NH3) for N2 (g) and H2(g)
  6. What is the general formula for calculating ΔS for a chemical reaction?
  1. What is the balance formula for this reaction?
  1. What is the value of ΔS for ammonia? ______
  2. What is the value of ΔS for nitrogen? ______
  3. What is the value of ΔS for hydrogen? ______
  4. Show the work for the calculation of ΔS below:
  1. Justify the value of ΔS for the above example (explain!):
  1. What is the significance of the value of –TΔS?
  2. A reaction is spontaneous if the value of ΔG is ______
  3. A reaction is at equilibrium if the value of ΔG is ______
  4. A reaction is spontaneous in the REVERSE direction if the value of ΔG is ______.
  5. For the melting of water,
  6. The value of ΔH is ______
  7. The value of ΔS is ______
  8. What happens to the value of –TΔS as temp goes up? ______
  9. What if we drop T<0 for the reaction as written above. Explain in your own words what would happen.
  10. For sample exercise 19.6:
  11. Show the formula for ∆G:
  1. Show your work and solve:
  2. For sample exercise 19.7:
  3. What is the value of ∆G for PCl3 (g)? ______
  4. What is the value of ∆G for P4 (g)? ______
  5. What is the value of ∆G for Cl2? ______
  6. Show your work to solve below:
  1. For sample exercise 19.8:
  2. Explain in your own words (maybe use a little math or diagram) part a.
  1. Now show the work to solve:

Extra Credit: