**Return to SYLLABUS **

** Old First Quizzes**

**First Quiz, 1998**

**1 - What are the SI units of pressure? (Give
the answer in units of length, mass and time.)**

**2 - Calculate the value of the gas constant R
in**

**a) L-bar/mol-K**

**b) meters3-bar/mol-K**

**(If you're suffering brain lock, and can't
remember R in L-atm/mol-K or in J/mol-K, just ask and I'll sell one
of them to you. Circle the units of the value you would like to
purchase.)**

**First Quiz**

**Spring, 1997**

**1 - Calculate the density of CO2 at a pressure
of 300 atm and a temperature of 400 K.**

**a) Using the ideal gas law, calculate the
density in grams/L. (If you need it, I'll sell you the value of
R.)**

**b) At these conditions, the compressibility
factor, Z, of CO2 is 0.69. Calculate the density of carbon
dioxide.**

**c) Are attractive or repulsive intermolecular
forces stronger under these conditions?**

**Justify your answer.**

**d) Which density, the one in (a) or the one in
(b), should be more accurate? Why?**

**(Note: You don't need to have calculated either
density to answer this question.)**

**First quiz**

**Spring, 1995**

**1 - Consider the differential**

**3x2y2 dx + 2 xy3 dy.**

**Is this differential exact or inexact? Show
why.**

**2 - Find the differential of the pressure of a
Van der Waals gas, which has the equation of state:**

**(P + a/V _{m}^{2})(V_{m} - b) = RT. (Hint: first solve for the pressure, then find
the differential.)**

** Old Second
Quizzes**

**Spring, 1995 **

**Two moles of O2, with _Cv = 20.8 J/mol-K, are
warmed so quickly that q = 0 (an adiabatic process). The temperature
is increased from 25.0 oC to 35.0 oC.**

**a) Calculate DU.**

** b) Calculate DH.**

** c) Is the gas being compressed or
expanded? Explain, using the sign of the work as your clue.
**

**Second Quiz**

**Spring, 1997**

**1 - Is the differential x2y dx + xy2 dy exact
or inexact? Show your work.**

**2 - a) Write the most general equation for P-V
work.**

**b) For a particular irreversible process, the
work was 300 Joules. **

**i) Was the process an expansion or a
compression? Explain your reasoning.**

**ii) What, if anything, can we say about the
value of work if the process were carried out reversibly?**

**Second quiz**

**Spring, 1998**

**1 - Consider the differential**

**3 x2y2 dx + 2 xy3 dy.**

**Is this differential exact or inexact? Show
why.**

**2 - An ideal gas expands from V1 = 1.00 L, P1 =
10.0 atm to V2 = 10.0 L, P2 = 1.00 atm, at a constant temperature of
25oC.**

**a) Calculate w if the external pressure is a
constant 1.00 atm.**

**b) Calculate w if the process is
reversible.**

**Old Third Quizzes**

**Quiz Number 3, 1996**

**Let's fiddle around with 2.00 moles of O2(g),
assuming it behaves ideally. _Cv = 2.7R**

**The gas is expanded reversibly from 1.00 liters
to 10.00 liters at a constant pressure of 10.0 atmosphere. The
initial temperature is 60.9 K.**

**i) What is the final temperature? (If you can't
do this, I'll sell you the final temperature.)**

**ii) Calculate DU.**

**iii) Calculate DH.**

**iv) Calculate w, in Joules.**

**Third Quiz, 1996**

**When one mole of methane, CH4, is burned in
excess oxygen in a bomb calorimeter, 885.3 kilojoules of heat are
evolved.**

**a) Determine DHcombustion for methane. Assume T
= 298 K.**

**b) If the molar heat of formation of CO2 is
-393.5 kJ/mole, and of water is -285.8 kJ/mole, use the data above to
**

**Quiz Number 3, 1997**

**When 7.80 grams of benzene, C6H6, are burned in
a bomb calorimeter, 327 kJ of heat are evolved. Assume the
temperature is 25 oC. (Atomic weights: C: 12.0 g/mol; H: 1.0
g/mol)**

**a) Calculate the molar enthalpy of combustion
of benzene, in kJ/mol.**

**b) Show, algebraically, how you could use the
answer to (a) and the heats of formation of carbon dioxide and water
to calculate the molar heat of formation of benzene.**

**Be as specific as possible; for instance,
indicate by how much you would multiply each of the heats of
formation in your calculation.**

**Third Quiz, 1998**

**When one mole of liquid methanol, CH3OH, is
burned in excess oxygen in a bomb calorimeter, 726 kilojoules of heat
are evolved.**

**a) Determine DHcombustion for methanol. Assume
T = 298 K.**

**b) If the molar heat of formation of CO2 is
-393.5 kJ/mole, and of water is -285.8 kJ/mole, use the data above to
, use the data above to calculate the molar heat of formation of
methanol.**

**Old Fourth Quizzes**

**Fourth Quiz, 1998**

**Let's play with 0.100 moles of helium, which we
can assume behaves ideally. You should know the molar heat capacity
of He, but I'll sell it to you if necessary. We'll start with 10.0
liters of He at 300K, and compress it using a constant pressure of
1.00 bar until the volume is 1.00 L and the final temperature is 350
K.**

**a) How much heat was absorbed or released by
the gas?**

**b) If the process had been an irreversible
adiabatic compression to 1.00 L, what would the final temperature
have been?**

**c) (A quickie) Why does DH = (gamma)DU for the
above processes?**

**Fourth Quiz, 1997**

**Consider the reaction, at 25oC.**

**pyruvate(aq) + 2 O2(g) = acetate(aq) + CO2(g)
DHo = -297.3 kJ/mol**

**1 - Calculate DUo for the reaction, at
25oC.**

**2 - If DCP = 50.0 J/mol-K, calculate DHo for
the reaction, at 37 oC.**

**Fourth Quiz, 1996**

**Let's fiddle around with an adiabatic process
involving 2.00 moles of He, which we can assume behaves ideally. As
you are undoubtedly aware, _Cv = (3/2)R for He and all other
monatomic gases. Let's have the initial temperature be 300 K, and the
initial volume be 10.0 liters. If the final temperature is 5.00
liters and the final temperature is 400K, **

**a) Calculate DH of helium.**

**b) Calculate the work done by the
surroundings.**

**c) Calculate DSHe.**

**d) Was the process reversible, irreversible, or
impossible? Use the second law to solve this problem. (If you
couldn't do (c), assume the answer was DS = -3.0 J/K.)**

**Old Fifth Quizzes**

**Quiz No. 5, 1998**

**1 - Give an example of a spontaneous process
for which DS is negative. Why doesn't this process violate the second
law of thermodynamics?**

** **

**2 - Consider all isothermal processes involving
an ideal gas. Which of the following statements must be true? If so,
show why. (Give an equation.) If not, give an example.**

**a) q = 0**

**b) DU = 0**

**c) DH = 0**

**d) DS = 0**

**e) DSuniverse = 0**

**Quiz Number 5, 1997**

**1 - Consider a reaction for which DHorxn = -
75.0 kJ/mol, and DSorxn = 250. J/mol-K.**

**a) Calculate the equilibrium constant for the
reaction at 25oC.**

**b) Calculate Keq at 50oC, assuming DCP =
0.**

**c) Are your answers consistent with
LeChatelier's Principle, which predicts how the equilibrium will
shift if the temperature is changed? Explain.**

**Quiz number 5, 1996**

**Given the phase diagram, **

**P 900 ***

**r ***

**e 800 ***

**s ***

**s 700 ***

**u ***

**r 600 ***

**e ***

**(torr) 500 * **

**._______________________________________**

**500 600 700 800 900 1000**

**Temperature, oC **

**1 - Calculate the heat of sublimation of the
substance.**

**2 - Derive the Clapeyron equation,**

**dP/dT = DH/(TDV)**

**3 - Use the Clapeyron equation to show which
phase has the larger volume, the liquid or the solid.**

**Old Sixth Quizzes**

**Quiz number 6, 1998**

**1 - Given the plot of ln(Keq) vs 1/T,
**

**a) Calculate the heat of reaction.**

**b) Calculate DSorxn**

**Quiz Number 6, 1997**

**1 - Use the Clausius - Clapeyron Equation to
calculate the heat of vaporization of water if its vapor pressure is
23.76 torr at 25oC. Use the normal boiling point as your second
point. (I, of course, will sell you the equation if
necessary.)**

**2 - Let's assume the heat of vaporization of
water is, say, 40,656 J/mole at its normal boiling point. **

**a) What is the numerical value of the Gibbs
Free Energy of vaporization at this temperature and pressure?
Why?**

**b) Use your results in (a) to calculate the
molar entropy of vaporization at this temperature.**

**Sixth Quiz, 1996**

**a) If we dissolve 0.100 grams of a small
protein in 500 grams of water at 25 oC, calculate the molecular
weight of the protein if the solution exerts an osmotic pressure of
2.00 Pascal.**

**b) If a series of experiments gave the
following results:**

**mass of protein/L 0.20 0.40 0.60**

**Calculated MW of 24000 23500 23000**

**the protein, g/mol**

**calculate the "best" value of the molecular
weight of the protein.**

**Old Seventh Quizzes**

** **

**Old Eighth Quizzes**

**1 - What's the Gibbs Phase Rule? Define each
term.**

**2 - Draw the phase diagram for water and apply
the Phase Rule to calculate the number of degrees of freedom at
**

** a) the triple point. **

** b) 25oC and one bar pressure.
**

** (Hint: in case you can't recall the answer to
problem 1, you might be able to use your answer in problem 2 to help
you. There's more than one way to pass a quiz.)**

** Quiz Number 8**

**As you undoubtedly recall, the Nernst Equation,
at 298K, is **

** E = Eo - (0.0592/n)log(Q) **

**1 - Consider two Standard Reduction Potentials,
at 298K:**

** O2 + 4 H+ + 4 e- 6 2 H2O Eo =
1.229 volts**

** NAD+ + H+ + 2 e- 6 NADH Eo = -
0.113 volts**

**a) Calculate Eo, at 25oC, for the reaction
**

** 2 NADH + O2 + 2 H+ 6 2 H2O + 2
NAD+ {1.455 volts}**

**b) Now, calculate E* for the same reaction,
still at 25oC. E* is the voltage with pH = 7, and all other species
in their standard state. (If you couldn't do (a), assume your answer
was, oh, 6.000 volts.) {1.041 V}**

**c) Finally, using either value of õo,
calculate the voltage if the concentrations of all solutes were 0.10
moles/liter. (Have the pressure of O2 be its normal value in
air.) {1.375 V}**

**Old Ninth Quizzes**

**Consider the enzyme catalyzed reaction: 2 S =
P. If the proposed mechanism is **

** S + E = ES (forward rate constant k1,
reverse rate constant k-1) **

** S + ES = E + P (where k2 is the rate
constant.)**

**a) Using the steady state approximation for the
intermediate, ES, derive an expression for [ES] as a function of [S],
[E] and rate constants. {[ES] = k1[S][E]/(k-1 + k2[S])}**

**b) Assume that the rate of the last reaction is
the overall rate of the reaction, and derive an equation for this
rate, in terms of the concentrations of E and S, and rate constants.
{rate = k1k2[S][E]/(k-1 = k2[S])}**

**c) If the rate is given by:rate = k[E][S]2/(1 +
k'[S]), how could we force the reaction to be second order in
S? {Make [S] very small.}**

**d) Under the conditions in c), what would be
the rate determining step? Explain. {The last step}**

**1 - Consider the reaction **

** 2 A + B = D + E**

**Run [A],moles/L [B],moles/L Rate,Moles/L-sec11 1
0.100 0.100 .000100**

** 2 0.300
0.100 .00100 **

** 3 0.300
0.200 .000900**

**Calculate the parameters in the rate equation,
to 3 significant figures.**

**{Order w.r.t. A: 2.10; w.r.t. B: -.152; kr =
0.0100 L/mol-sec}**

**2 - If the reaction above were 2nd order in A
and zeroth order in B,**

** a) Predict a possible rate determining
step.**

** {A + A = A2}**

** b) Construct a plausible
mechanism.**

** {A + A = A2 (slow
step)**

** A2 + B = D + E Fast
step}**

** **

** Consider an aqueous
solution of sodium sulfate. There are lots (well, six) types of
potential energy terms between the various molecules in the solution,
e.g. ion - dipole, polarizability - dipole, etc. **

** For each of the ones that you can think of,
write the type of energy (or force) that exists, an example of a pair
of molecules that would be attracted by that form of potential
energy, and write as much as you can recall about the form of the
equation for the potential energy. This should include the power of
r in the denominator, and what properties of the molecules that
should be in the numerator.**

**Example: **

**Type of attraction Example Form of the
equation**

** ion - dipole Na+ ... H2O Ep = -
(Const.)(qNa+)(muH2O)cos(2)/r2**

**{ion - ion Na+ ….Cl- E =
Const(qNa)(qCl)/r **

** dipole - dipole H2O … H2O E = - Const
(muH2O)2/r4**

** ion - induced dipole Na+ …. H2O**

** dipole - induced dipole H2O …. H2O**

** dispersion H2O …. H2O**

**Old Tenth Quizzes**

**1 - A certain reaction may proceed by a direct
path or a catalyzed path. **

**If DS*path b = DS*path a + 40 J/mol-K, and
**

** DH*path b = DH*path a + 20
kJ/mol,**

** a) Which path has the greater rate constant
at 310 K, and by what ratio? (It is not necessary to calculate
either rate constant!) {Path A; 19/1}**

** b) Which path is the catalyzed path? (a or
b?) Explain. {Path A; lower EA)**

**2 - Consider the data for the reaction
**

** A = B + C**

**time, sec 0 10 20 30 40
50**

**[A], M 0.200 0.143 0.111
0.092 0.077 0.067**

**a) Find the order with respect to A. {Second
order}**

**b) Calculate the rate constant. (Units!) {0.25
L/mol-sec}**

**c) Calculate the concentration of A after 208
seconds.{0.0175 M}**

**d) Postulate a mechanism for the reaction,
indicating the slowest step.**

** {A + A = A2 (RDS)**

** A2 = A + B + C}**

**1 - The energy of a one electron atom or ion
with Z protons is given by the equation:**

** E = -Z2B/n2, where B = 2.18x10-18
Joules.**

** a) Calculate the wavelength of the photon
emitted when an excited state electron on Li2+ falls from a 3d
orbital to a 2p orbital. {Lambda = 72.9 nm}**

** b) Pretend DE in a) is 2.73x10-18 Joules.
Use the Virial Theorem to calculate the change in potential
energy of the electron during the process in a). {5.46x10-18
J}**

**Old Eleventh Quiz**

** 1 - Let's play with an approximate
one-dimensional pib wavefunction, psi = N(L - x)x, where 0 > x
> L.**

** a) Show that psi is normalized if N =
(30/L5)2**

** b) If ^H = -(h/2(pi))2/2m)d2/dx2, is psi an
eigenfunction of the Hamiltonian? Show why. {No, it's
not.}**

** c) Use the average value postulate (Postulate
4) to calculate the average value of the
energy. {5h2/4(pi)2mL2}**

**Old Twelfth Quiz**

**A bulb contains a mixture of gaseous ammonia
and methane. **

**a) If the sample is irradiated (zapped) with
photons having wavelengths around 0.10 cm, which molecules are likely
to absorb the radiation? {ammonia}**

**b) What properties of the substances are
necessary for absorption in a)? That is, what is the gross selection
rule requirement? {The molecule must be polar.}**

**c) Now, we irradiate the samples with radiation
having a wavelength of around 4.4x10-4 cm. Which molecules can
absorb this radiation? {Both}**

**d) What molecular property is necessary (Again,
what is the gross selection rule?) for absorption at this wavelength?
{The dipole moment must change as the molecule vibrates.}**

**e) Which of the experiments (if either) will
tell us the bond length in ammonia? {Both}**