Chem 125  Fall 2004

Study guide for Final Exam

 

The exam will be held Monday December 6, in CB 385, from 8am until 10am.  Bring a calculator.  Partial credit for multi-step problems will be given ONLY if you show your work.  In some cases full credit will not be given UNLESS you show the logical progression of your work.  Some of the problems are designed to test your ability to solve chemical problems (such as those in Atkins and Jones, the pre-labs, and quizzes).  Other questions will be designed to test your understanding of the chemical concepts discussed in lecture.  Equations (e.g. PV = nRT), constants (e.g. R), a table of potentially useful information, and a “bare bones” periodic table will be given to you.

 

-  I will have an “open door” office hours policy in effect during Dead Week.  You are welcome to drop by my office to ask questions.

 

The exam covers primarily the material in Chapters 6 and 7; however, it is comprehensive.  This list is not guaranteed to be comprehensive, but it is a very good idea to review the following topics in preparation for the exam.

 

General:

1) basic stoichiometry as expected on the two midterm exams and the lab exercises

2) Your answers must ALWAYS have the appropriate units!

 

Chapter 6:

1) DU = w + q; definitions of w and q

            evaluating w and q for isothermal, isobaric, isochoric processes

2) using P vs. V diagrams (as in the in-class exercises)

3) using heat capacities to calculate q lost or gained by materials

4) calculating q required to get from Ti to Tf on a heating curve (including phase changes; see Fig 6.26)

5) Cv vs. Cp for real and ideal gases

6) calculating DHº for a reaction (see handout given in class)

            using DHfº values from Appendix 2

            using bond enthalpies and appropriate enthalpies for phase changes

7) using DHº for a reaction in stoichiometric calculations (e.g., problems 6.41 and 6.97)

8) Hess’ Law of heat summation (problems 6.59 and 6.61)

9) Born-Haber cycle calculations (problem 6.67)

 

Chapter 7:

1) thermodynamic and statistical definitions of DS

2) what happens to DS as the following change:

            P; V; T; molar mass; phase

3) calculations of DSsys; DSsurr and DSuni (e.g., problem 7.43 and in-class problem)

4) DG = DH -TDS

5) definition of “spontaneous” process using DG or DS

 

Chapter 1:

1) E = hn; c = ln

2) calculating the energy of electronic transitions in the H atom (Balmer-Rydberg formula)

3) quantum number: n, l, ml, ms (what do they specify?)

4) building up electronic ground state configurations (Pauli exclusion; Hund’s Rule)

            predicting ground state electron configurations for atoms and ions

            paramagnetic vs. diamagnetic ground states

5) periodic trends: atomic and ionic radii, ionization energy etc.

6) Photoelectric effect

            relationship between “work function” and ionization energy

 

Chapter 2:

1) identifying valence electrons for atoms and ions and predicting charges on ions

2) Coulombic model of ionic bonding

3) drawing satisfactory Lewis diagrams, including resonance structures

            octet rule; correct # valence electrons

4) formal charge calculations for resonance structures

5) polar vs. non-polar covalent bonds (electronegativity scale)

 

Chapter 3:

1) using VSEPR to predict molecular shape (combined with electronegativity to predict polarity)

2) Valence bond theory:

ideal bond angles for hybrid orbitals (sp, sp2, sp3, dsp3, d2sp3)

s and p bonds

3) bonding, non-bonding, and antibonding molecular orbitals

4) calculating bond order using MO theory

            HOMO/LUMO

bond length and strength

 

Chapter 4:

1) application of the ideal gas law (PV = nRT)

2) calculating partial pressures of gases in a mixture; mole fraction

3) reaction stoichiometry with gases

4) relationship between rate of effusion and molar mass of gases

5) qualitative understanding of the terms “a” and “b” in the Van der Waals equation (what do they account for in the behavior of real gases?)

            what are the assumptions in the Kinetic Theory of Gases? How does the VdWaals equation improve the prediction of behavior for real gases?

 

Chapter 5:

1) understand the relative strengths of the forces described in Table 5.1 (rank in order of strength; understand application of Coulombic model to different interactions); how does the Joule-Thomson effect illustrate the concept that “bond formation releases energy; bond breaking requires energy”?

2) rationalize differences in melting and boiling points based on molecular structure, geometry, polarity and chemical composition

3) understand the relationship between density and packing in cubic unit cells of solids (fcc, bcc, primitive cubic)

  

  

Preparation Strategy:

- Work as many problems as you can (this works best after you have read the textbook).  Here are some specific suggestions for review problems from your text:

 

Chapter 6: 9, 15, 23, 25, 29, 33, 37, 39, 41, 47, 59, 61, 67, 69, 73, 81, 89, 91, 93, 97, 109

 

Chapter 7: 1, 5, 7, 17, 19, 23, 31, 37, 43, 45, 47, 51, 59, 69, 73, 79, 81, 87

  

         Chapter 1: 7, 13, 23, 43, 51, 59, 61, 77, 83, 97, 101

 

         Chapter 2: 3, 15, 23, 43, 47, 53, 69, 85, 91, 93 

 

Chapter 3: 37, 47, 55, 65, 67, 69, 77, 81, 85, 93a,b

 

Chapter 4: 35, 43, 45, 51, 57, 63, 71, 75, 81b, 83, 85, 87, 91, 101

 

Chapter 5: 11, 13, 19, 27, 35, 85

 

- Review all the quizzes and make sure you can solve all the questions.

 

- Review Exams #1 and #2; make sure you can solve all the questions.

 

- Review in-class assignments and make sure you understand the solutions to the problems