Use the phase rule to determine the degrees of freedom of each of the following equilibrium systems and give a possible set of variables that may be specified:

a: NaCl crystals suspended in an aqueous NaCl solution

b: Humid air in equilibrium with condensed water (dry air may be considered a single species)

c: a vapor-liquid mixture of four hydrocarbons

d: a gaseous mixture of H2,Br2, and HBr, given that the single reaction: H2 + Br2 <-> 2HBr, has proceeded to equilibrium

Health in the Workplace

Part 1

Don Hayward is employed as a chemical engineer at ABC Manufacturing. Although he does not work with hot metals himself, he supervises workers who are exposed to hot metals eight hours a day, five days a week. Don becomes concerned when several workers develop respiratory problems and complain about "those bad smelling fumes from the hot metals". When Don asks his superior, Cal Brundage, about air quality in the workplace, the reply is that the workplace is in full compliance with OSHA guidelines. However, Don also learns that OSHA guidelines do not apply to chemicals that have not been tested. A relatively small percentage of chemicals in the workplace have actually been tested. This is also the case with the vast majority of chemicals workers are exposed to at ABC.

Should Don do anything further, or should he simply drop the matter?

Part 2

Don goes to ABC's science library, talks to the reference librarian about his concerns, and does a literature search to see if he can find anything that might be helpful in determining why the workers have developed respiratory problems. He finds the title of an article that looks promising and asks the reference librarian to send for a copy. The librarian tells Don that the formal request must have the signed approval of Cal Brundage.

Don fills out the request form and sends it to Cal's office for approval. One month later the article has still not arrived. Don asks Cal about the request. Cal replies that he doesn't recall ever seeing it. He tells Don that it must have gotten "lost in the shuffle." Don fills out another form and this time personally hands it to Cal. Cal says he will send it to the reference librarian right away.

Another month passes by and the article has not arrived. Don mentions his frustration to the reference librarian. He replies that he never received a request from Cal.

What should Don do now?

Explain why polyacetylene is an electrical conductor whereas polyethylene.

1.7 kg/s NH3 and 20 m3/s air at 25 oC and 1 atm are fed into a reactor in which the ammonia is completely consumed. The product gas emerges at 300 oC. Calculate the rate at which heat must be transferred to or from the reactor, assuming operation at approximately 1 atm. You must show full systematic working.

The standard heat of reaction for the oxidation of ammonia is given below: 4 NH3(g) + 5 O2(g) ? 4 NO(g) + 6 H2O(v): ?Hor = -904.7 kJ/mol
Note: The enthalpy of NO at 300 oC, relative to 25 oC, is 8.453 kJ/mol

We have the reaction  
2 A(aq) +B(aq) + 3 C(aq) ? 2 D(aq) + 2 E(aq) + 3F(aq) .  
At 25^oC, we start with a solution that is 0.977 M in A(aq), 0.655 M in B(aq), and 0.911 M in C(aq). There is no D(aq), E(aq), or F(aq) present. Equilibrium is established, and at equilibrium, the concentration of C(aq) is 0.677 M. What is the value of the equilibrium constant, K, for this reaction? What is the value of ?G^o for this reaction? For this reaction, we have another experiment where we only start with D(aq), E(aq), and F(aq). At equilibrium, the concentrations of D(aq), E(aq), and F(aq) are, respectively, 0.211 M, 0.322 M, and 0.255 M. What is the concentration of B(aq) at equilibrium? The temperature is still 25^oC.

a) What are edge and screw dislocations and why are they important in metals?;

b-) Make a 2D sketch of an edge dislocation using the ball and stick model of the crystalline state and show its salient features such as extra-half plane, dislocation core, state of stress above and below the slip plane, and Burger’s vector. What does the Burgers vector designate?;

(c-) Why does dislocation slip take place on closed packed crystallographic planes and along close packed crystallographic directions? Why is screw dislocation slip easier than edge dislocation slip in metals? Why dislocation motion (slip) is not possible at room temperature in ionic solids such as NaCl?

- The dissolution of polymer can be thermodynamically described in 2 steps. Describe it.

- Describe the process of protein flocculation at its isoelectric point?

1. What are the main feed and product components of FOB(fuel oil block) and LOB(Lube oil block)?

2. Which particular unit does the following final product come from

a. gasoline

b. jet fuel

c. candle wax

d. naphtha

3. where does the refinery get their water from and how do they handle water disposal?

4. how do they process their chemical waste disposal?

A 10.0 m³ tank contains steam at 250°C and 10.0 bar. The tank and its contents are cooled until the pressure drops to 1.8 bar. Some of the steam condenses in the process.

(a) How much heat was transferred from the tank?

(b) What is the final temperature of the tank contents?

(c) How much steam condensed (kg)?

Steam produced in a boiler is frequently “wet”—that is, it is a mist composed of saturated water vapor and entrained liquid droplets. The quality of a wet steam is defined as the fraction of the mixture by mass that is vapor.

A wet steam at a pressure of 5.0 bar with a quality of 0.85 is isothermally “dried” by evaporating the entrained liquid. The flow rate of the dried steam is 52.5 m³/h.

(a) Use the steam tables to determine the temperature at which this operation occurs, the specific enthalpies of the wet and dry steams, and the total mass flow rate of the process stream.

(b) Calculate the heat input (kW) required for the evaporation process.

o Explain in your own words and without the use of jargon (a) the three ways of obtaining values of physical properties;

o (b) why some fluids are referred to as incompressible;

o (c) the “liquid volume additivity assumption” and the species for which it is most likely to be valid;

o (d) the term “equation of state”;

o (e) what it means to assume ideal gas behavior;

o (f) what it means to say that the specific volume of an ideal gas at standard temperature and pressure is 22.4 L/mol;

o (g) the meaning of partial pressure;

o (h) why volume fraction and mole fraction for ideal gases are identical;

o (i) what the compressibility factor, z, represents, and what its value indicates about the validity of the ideal gas equation of state;

o (j) why certain equations of state are referred to as cubic; and

o (k) the physical meaning of critical temperature and pressure (explain them in terms of what happens when a vapor either below or above its critical temperature is compressed). In addition, pick either a pure liquid or gas (i.e., ethanol, oxygen, eugenol, helium) that sparks your interest and provide some of its physical properties, its uses, and why you chose it. Enjoy!

Oil (s = 0.850 and µ = 14.0 cP) is flowing out the end of a 100 ft long pipe with a diameter of 4.026 in at the maximum flow rate to remain in the laminar flow regime. (a) At what angle, in degrees, would you have to tilt this pipe so that the pressure drop is zero? Is the angle uphill or downhill? l (b) How much work is lost to friction? Give your answer in lbf ft/lbm. Answers should be 0.094 degrees downhil and 0.164 lbf ft/lbm

200 SCMH of dry CO2 is bubbled through a vessel that contains liquid acetone. The gas leaves the vessel with a relative saturation of 90% at 320 K. All process streams can be assumed to be at1 atm. Calculate: a) the dew point temperature of the exiting gas. b) the mole fraction of acetone in the exiting gas. c) the rate at which acetone is stripped from the liquid phase (molar flow rate). d) the actual volumetric flow rate of the exiting gas. e) the temperature to which the gas would have to be cooled to condense 95% of the acetone in the gas stream

Solid particles of density 2500 kgm-3 were packed into a fluidized bed reactor of 2 m in height and 0.04 m2 in cross-sectional area. The mass and height of the packed bed are 45 kg and 1 m, respectively. The surface-volume mean diameter of the particles is 1 mm.

(a) Determine the porosity of the packed bed.

(b) Determine the pressure drop across the bed when a liquid of density 800 kgm-3 and viscosity of 0.002 Pa s flows through the bed at a flow rate of 1.44 m3h-1.

(c) What is the pressure drop across the bed at the point of fluidization if the porosity is 0.6?

Thanks in advance

If volume changes (for example, piston is pushed down or moved up), how would the total pressure change (T=constant)? How would mole fraction of the components change: in vapor? in liquid?