Name

CH 342 Physical Chemistry II

Hour Exam I February 13, 2003

This examination consists of 10 short answer/multiple choices questions and four problems. For the problems, you must show your work and all answers must include units and appropriate significant figures.

Useful Constants

c = 2.99792 x 108 m/s

me = 9.109389 x 10-31 kg

g = 9.80 m/s2

h = 6.626 x 10-34 J-s

k = 1.380658 x 10-23 J/K

R = 0.082057 L-atm/mol K or 8.3145 J/mol K or 0.0831451 L-bar/mol K

NA = 6.022137 x 1023 /mole

Useful Conversions

1 atm = 760 torr = 101325 Pa =1.01325 bar

100 J = 1 L-bar or 101.325 J = 1 L-atm

For an ideal noble gas Cv = 3/2R and Cp = 5/2R

Questions

1) Which of the following is an intensive property

a) Volume

b) Mass

c) Temperature

d) Energy

2) Given an example of a heterogeneous mixture in a open system

3) Define the term critical point.

4) Which of the following is true for a reversible adiabatic process involving an ideal gas in a piston.

a) q=0

b) w=0

c) DU = 0

d) none of the above

e) all of the above

5) Give a brief definition of a reversible process

6) Which of the following is true for a reversible constant volume heating of a gas in a piston

a) w = 0

b) DU =0

c) P is constant

d) q = 0

7) What do the parameters a and b in the van der Waals equation for a particular compound tell you about that compound

8) If a reversible heat engine is cycling between a pressurized boiling water reservoir (150 °C) and a room temperature reservoir (22.0 °C), what is the efficiency of the engine?

9) Give a brief statement of the first law of thermodynamics

10) Sketch an isotherm for a real gas well below its critical temperature

Problems

1) Consider 800.0 mL of chlorine gas weighing 36.50 g at 273.15 K. What is the pressure of according to the van der Waals equation (a=6.579 barL2/mol2; b= 0.05622 L/mol)?

b) What is the compressibility at this molar volume

c)If the compressibility is 0.9280 at a molar volume of 3.241 L/mol, what is the second virial coefficient of chlorine at 273.15 K?

2) a) Using the attached table, calculate DH° for the following reaction

CO2 (g) + 4H2 (g) CH4 (g) + 2H2O (l)

b) if you performed the above reaction in a constant pressure calorimeter would you expect the calorimeter temperature to rise or fall? Explain.

c) 1.000 g of benzene is combusted in a bomb calorimeter. The resulting temperature rise was 4.174 K. The calorimeter constant for this instrument is 10.00 kJ/K. What is DU per mole for the combustion reaction? What is the balanced chemical equation for the reaction?

3) Calculate DU, DH, q, w, DS for the reversible isothermal expansion of 0.0500 moles of an ideal gas at 298 K from 300.0 mL to 500.0 mL .

4) Consider a gas with the following expression for the second virial coefficient

This expression is in terms of the reduced temperature of the gas.

a) What is the Boyle temperature in terms of the TR?

b) If the critical constants for carbon dioxide are 304 K, 0.0956 L/mol, and 73.9 bar. What is the Boyle Temperature for carbon dioxide based on the above expression.