Here is Exam I from WN 05

Chapter 11:

Vocabulary Checklist: London dispersion forces ; polarizability ; surface tension ; adhesion ; Vapor Pressure ; boiling point ; molecular solids ; covalent network solids ; ionic solids

Concept checklist:

1. Explain the two major forms of intermolecular force: London dispersion and dipole-dipole.
2. Explain what a hydrogen bond is and why it is important for our existence.
3. Explain surface tension, and how adhesion and cohesion relate to each other.
4. Understand the energy changes associated with all phase changes and how to calculate them.
5. Explain dynamic equilibrium and how it relates to vapor pressure.
6. Explain what Critical temperature and pressure are.
7. Understand the makeup of a phase diagram and label all the points.
8. Explain all four major kinds of bonding in solids.

 Chapter 11 Problems: 1,4,9,15,17,19,25,33,35,37,39,43,55,79,85,105

Some exams questions from chpt 11 from previous years...

1. [10] The normal boiling points of HF, HCl and HBr are 19 ºC, -67 ºC and -85 ºC. Explain in detail why the trend is the way that it is (5) and why there is such a huge drop from HF to HCl. (5)
2. [10] Define boiling point. (4) Atmospheric pressure on the surface of Mars is ~1% of that on Earth. What would be the boiling point (value or range is fine) of HF on the surface of Mars? Explain your answer.(6)
3. [14] Lets us say for a moment your chemistry professor wants you to calculate how much energy would be required to take a mass (m_HF) of liquid HF at some temperature, T_i to a gas at some final T_f. Besides the data points m_HF, T_i, and T_f what other values would you need? Think through the entire calculation. There are more than 2, less than 6. (6) Assuming you had those data points, briefly explain (in words) what you do to calculate the energy needed.(8)
 4. [6] There are two solid bonding 'flavors' of the four that exhibit high melting points and poor thermal and thermal conductivity. Name them (4) and give an example of each (2).

Vocabulary: insulator, conductor, semicondictor, superconductor, polymer, plastic, LCD, LED
Concept checklist:
1. Explain what a semi conductor is and why we make them
2. Give general properties of insulators
3. Give general properties of superconductors
4. Give general properties of plastics and polymers
5. Expalin differenc ebetween addition and condensation polymerization
6. Know requirements/purposes for materials used in medicine, electronics, optics and nanotechnology

Chapter 12 problems: 7, 13, 29

Chapter 13:

Vocabulary Checklist: solubility ; saturated ; colligitive property ; osmosis ; hypotonic ; hypertonic ; isotonic ; solution ; suspension ; colloid

Concept checklist:
1. Understand the solvation process.   
2. Explain Henry's law.
3. Understand and use all the units of concentration including molality.
4. Explain and use Raoult's law.
5. Calculate freezing point depression, boiling point elevation in electrolyte and nonelectrolyte soln's
6. Explain and calculate osmotic pressure.

The following will be given to you on the exam, no need to memorize these equations/constants:

Exam questions from previous years:
1. (30) The vapor pressure of pure ethanol at 25.0 °C is 85.0 torr. The normal boiling point and freezing point of ethanol is 78.4 °C and -114.6 °C, respectively. The freezing point depression and boiling point elevation constants are 1.99 and 1.22 °C/m respectively. A solution is made by mixing NaCl dissolved in pure ethanol. With the exception of part d, all the following are at 25.0 °C.

a. The osmotic pressure is 17.11 atm. What is the molar concentration of the solution? (6)
            b. The density of this solution is 0.896 g/mL. Calculate the molality of the solution. (10)
            c. Calculate the vapor pressure of the ethanol solution. (8)
            d. Calculate the boiling point on this solution. (6)
2 (20) Your 5^th grade nephew approaches you. He has been spending a lot of time with a clear soda bottle. He has been taught that CO₂ is dissolved in the soda bottle. He has also observed a warm soda will lose fizz much quicker than a cold soda. He has several questions for you. All must be answered in language understandable to him. You can use words like Henry's law or Raoult's law, but only after you explain them. Small words, remember, he is only in 5^th grade.
        a. He asks why when he opens a bottle of soda, a bunch of carbon dioxide comes off. He knows there is CO₂ in the bottle before he opens it, but doesn’t understand why it comes out only when he opens the bottle. (6)
        b. He has also observed that a warm soda will lose fizz much quicker than a cold soda. Why is that? (7)
        c. He noticed that at the edge of the container, the liquid level seems to curve 'up' to meet the container. Why is that? (7)

CHAPTER 14:

Vocabulary Checklist: Reaction rate,  Rate laws, reaction order, half life, radioactive decay, carbon dating, Kinetic molecular theory, activation energy, transition state theory, reaction mechanism, elementary step, rate determining step

Concept checklist:
1. Explain what kinetics is and what it is a function of (four things)
2. How do you measures rate of reaction?
3. What is reaction order and how do you determine it using method of initial rates?
4. Do appropriate rate calculations knowing the rate of the reaction.
5. Derive the half life formula knowing the rate law of a particular reaction.
6. Explain radioactive decay rates and radio carbon dating.
7. Explain Kinetic Molecular Theory and how it relates to rate of reaction.
8. Explain Transition State Theory and how it relates to rate of reaction.
9. Understand properties of overall reaction mechanism and how they relate to elementary steps.

The following will be given to you on the exam, no need to memorize these equations/constants:

Exam questions from previous years:

1. (12) A CEM 141 student comes up to you and explains to you a particular decomposition reaction of compound ,. The student thinks that the reaction is second order. He knows that to determine the order of reaction you must do some sortof of experiment. There are, of course, two methods of confirming that the rxn is second order in ,. Explain both methods (as well as how to calculate k in each experiment) to the student in conversational terms (you can say 'measure the rate of reaction' and they know exactly what to do. They are not sure what to do with that information, though). They must be able to use your explanation as a guide. Be complete, and make sure the two methods are different. Don’t give me two version of the same kind of experiment.

2. (8) The following is proposed as a plausible reaction mechanism:

                        1 A  +  1 B -> 1 C  (slow)
                        1 C  +  1 B -> 2 D  (fast)

What is the overall reaction? (4) What is a plausible rate law for this reaction? (4)

3. (30) Consider data for the decomposition of HI into H₂ and I₂ .

a. (4) What is the order of reaction?
b. (10) What is the COMPLETE rate law (with rate constants) at 400 ºC and 500 ºC?
c. (8) What is the value of the collision factor?
d. (8) What is the value of the activation energy?