Final Examination. Multiple Choice Questions. 1. The Virial expansion of the Compressibility Factor for a van der Waals gas is:

Size: px

Start display at page:

Download "Final Examination. Multiple Choice Questions. 1. The Virial expansion of the Compressibility Factor for a van der Waals gas is:"

Shanon Quinn
5 years ago
Views:

1 CHEM 331 Physical Chemistry I Fall 2013 Name: Final Examination Multiple Choice Questions 1. The Virial expansion of the Compressibility Factor for a van der Waals gas is: Z = The Boyle Temperature T B for a van der Waals gas is given by: a) b/a b) a/rb c) Ra/b d) ab e) none of the above 2. For liquified Propane at 0 o C and under 100 atm pressure, we have: Determine. = 3 x 10-4 K -1 = 5 x 10-5 atm -1 a) 1.7 atm/k b) 15 atm/k c) 6 atm/k d) 45 atm/k e) 2.3 atm/k

2 3. From Joule's experiment involving the expansion of a gas into a vacuum, one directly deduces: a) = 0 b) = 0 c) = 0 d) = 0 e) = 0 4. The Heat Capacity C v of an Ideal Monotamic Gas is: a) 3/2 RT b) 3/2 R c) 5/2 R d) 5/2 RT 5. The 3 rd Law of Thermodynamics is used to deduce: a) the molar heat capacity of atomic solids must be constant regardless of their atomic weight. b) the heat capacity near the absolute zero is proportional to T 3. c) the entropy of all compounds at T = 0 Kelvin is zero. d) the heat capacity of all substances must be either finite or zero at T = 0 Kelvin. e) none of the above. 6. For a system capable of P-V work only, which of the following may not apply to an irreversible process: a) (ds) U,V > 0 b) (dh) T,P < 0 c) (da) T,V < 0 d) (dg) T,P < 0 e) none of the above

3 7. When a Rubber Band is stretched with a force f such that its length changes by dl, its Gibb's Free Energy change is expressed by: dg = -S dt + V dp + f dl A Maxwell Relation stipulates that - is equal to: a) b) c) d) e) 8. The Chemical Potential of the i th component in a multicomponent system, i, is defined by: a) b) c) d) e) 9. For a Negative Deviation binary solution, which of the following is not correct: a) It has a maximum boiling azeotrope. b) In the limit of infinite dilution, each component obeys Henry's Law. c) In the limit of mole fraction one, each component obeys Raoult's Law. d) H mix = 0.

4 10. For Water: Normal T m = K density (Ice) = 0.92 g/cm 3 density (Water) = 1.00 g/cm 3 H fus = kj/mol The melting point of Water under 100 atm pressure is: a) 0.32 o C b) o C c) o C d) o C e) 0.71 o C

5 Short Answer Questions 1. The Compressibility Factor Z for N 2 gas is 0.85 at 200K and mol/cm 3. Determine the Pressure of the gas in SI units.

6 2. A resistor is immersed in a bath of crushed Ice in a Dewar flask. A current of 2 Amperes passed through the resistor for 300 sec (5 min) results in the melting of some of the Ice. The resistance is 18. (Recall, the electrical work done on a resistor in passing a current through it is given by W = I 2 Rt.) a) Find Q, W and U for the System if the system is the Resistor. b) Find Q, W and U for the System if the system is the Ice-Water. c) Describe the nature of the Wall which surrounds the Ice-Water system. b) Suppose all the Ice melts before the heating is complete. Will that affect your calculations above? Explain.

7 3. Consider a Freezer apparatus, which maintains a low temperature (T c ) of -18 o C inside an insulated box, in a room at 25 o C (T h ), by means of a compressor driven by an electric motor. Idealize this device and treat it as a Carnot "Engine". a) Determine the signs of W, Q h and Q c. b) By direct application of the definition of the Entropy, determine Q h /Q c. c) Determine the "efficiency" of this device, = W / Q c

8 4. Vapor pressure data for the Ethanol-Chloroform system at 35 o C are given below: x e y e P [kpa] Determine the Activity Coefficients e and c for this system when x e = 0.6. (Activity coefficients are defined according to the Ideal system; *.)

9 5. Dehydration of Calcium Hydrogen Phosphate Dihydrate proceeds according to: CaHPO 4 2H 2 O(s) CaHPO 4 (s) + 2 H 2 O(g) Data: Compound o G f [kj/mol] CaHPO 4 2H 2 O(s) CaHPO 4 (s) H 2 O(g) a) Determine the Equilibrium Constant K p for the above dehydration reaction. b) Determine the vapor pressure of Water in equilibrium with Calcium Hydrogen Phosphate Dihydrate and the Anhydrous salt. (P o = 1 atm)

10 6. Consider the Electrochemical Cell: Cd(s) CdCl 2 (m) AgCl(s) Ag(s) a) Write the Cell Reaction for this Cell. b) Determine the Reaction Quotient Q for this cell in terms of the molality of the CdCl 2. (Hint: First determine the relationship between m ± and m.) c) How might you determine o Cell from Cell vs. m data.

11 6. The Phase Diagram for solid Mercuric Iodide (HgI 2 ), yellow and red forms, is given below. This diagram shows a maximum near 5000 atm. What can you infer about the properties of the red and yellow forms of HgI 2 in the vicinity of the maximum? You must provide support for your answer.

Review of differential and integral calculus and introduction to multivariate differential calculus.

Chemistry 2301 Introduction: Review of terminology used in thermodynamics Review of differential and integral calculus and introduction to multivariate differential calculus. The properties of real gases: