A large deep lake, which initially had a uniform oxygen concentration of 1 kg/m3 , has its surface concentration suddenly raised and maintained at 9 kg/m3 concentration.
a. Draw a picture of the physical process. Select a coordinate system to describe this diffusion process. Write the general form of the oxygen species continuity equation for this system.
b. Reduce the general differential equation for the mass transfer process for the transfer of oxygen into the lake without the presence of a chemical reaction.
c. Reduce the general differential equation for the mass transfer process for the transfer of oxygen into the lake occurs with the simultaneous consumption of oxygen by a first order biological reaction, ?? = −??0.
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in one full, elaborate paragraph compare and contrast the desalination processes RO AND MSF
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in one pargraph, compare and contrast between the disallination processes, msf and rp
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Bacteria are not limited to organic matter as a source of electrons or energy. Autotrophic denitrification occurs when NO3- is used as an electron acceptor and converted to N2 gas and H2 gas is used a source of electrons.
Below are the two half reactions we will be working with.
2NO3- + 10e- -> N2
2H+ + 2e- -> H2
Which reaction needs to be reversed? Enter the letter A or the letter B
Balance the half reaction for the conversion of nitrate to dinitrogen gas. Input the reaction co-efficient for each component of the half reaction in the blank provided. The co-efficient might be 1 in some cases.
2NO3- + e- + H+ -> N2 + H2O
Balance the half reaction for the conversion of hydrogen gas to hydrogen ions. Questions 12-13 are asking for the reaction co-efficients for each piece of the reaction. The co-efficient might be 1 in some cases.
H2 + -> 2e- + H+
Combine and balance both equations.
NO3- + H+ + H2 -> N2 + H2O
How many electrons were transferred?
What is the redox potential of this reactions in volts? E0cell = ?
Using the Nernst Equation, calculate the Gibbs Free Energy to deduce how many kilojoules are available to do work based on the stoichiometry you determined? ΔG = -nFΔE, where F = 96.48 kJ (mol e-) (Report your answer to 3 decimal places)
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Prepare cyclohexene from cyclohexanol. The cyclohexanol and phosphoric acid (catalyst) are placed in the distillation flask.
a) During the distillation process, why the receiving vessel be sitting in an ice bath? Why need to distil slowly?
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1. Is it reasonable to say that enzymes lower the energy of the transition state for a reaction?
| Yes. Like other catalysts, enzymes speed up reactions by lowering the activation energy, which is the energy of the transition state. |
| No. Since enzymes change pathways of reactions, we cannot say that they lower the energy of the transition state. |
2. Why is the reaction faster when the liver is ground up?
| Grinding speeds up the reaction of formation of catalase in the liver. |
| Grinding increases the solubility of catalase. |
| Grinding increases the surface area. |
| Grinding allows for more catalase to be extracted from the liver to the solution. |
3. Energy profile for conversion of methyl isonitrile (H3CNC) to its isomer acetonitrile (H3CCN). How does the energy needed to overcome the energy barrier compare with the overall change in energy for this reaction?
The magnitude of energy needed to overcome the energy barrier is about the same as the magnitude of the energy change in the reaction.
The magnitude of energy needed to overcome the energy barrier is lower than the magnitude of the energy change in the reaction.
The magnitude of energy needed to overcome the energy barrier is greater than the magnitude of the energy change in the reaction.
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What is the effect of the BOD coefficient (i.e., the biodegradability of the waste in the effluent) on the shape of the DO sag curve?
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The vapor-liquid equilibrium data for heptane – ethylbenzene at 1 atm pressure is given below:
|
x |
0 |
0.10 |
0.20 |
0.40 |
0.50 |
0.60 |
0.70 |
0.90 |
1 |
|
y |
0 |
0.25 |
0.45 |
0.65 |
0.74 |
0.82 |
0.86 |
0.96 |
1 |
A feed mixture containing 40 mol% heptane and 60 mol% ethylbenzene is to be fractionated at 1 atm pressure to produce a distillate containing 95 mol% heptane and a bottom product stream containing 96 mol% ethylbenzene.
Determine the minimum reflux ratio if the feed is a saturated liquid.
Determine the minimum reflux ratio if the feed is a saturated vapor.
Determine the minimum reflux ratio if the feed is an equilibrium mixture of liquid and vapor, with 20% vapor.
Determine the minimum number of theoretical plates using McCabe-Thiele graphical method.
Determine the minimum number of theoretical plates using Fenske equation.
For a saturated liquid feed and a reflux ratio that is 2.25 times the minimum, determine:
-The number of theoretical stages, using McCabe-Thiele graphical method.
-The optimum feed stage location.
-The actual number of stages if the average column efficiency is 58%.
-The top product and bottom product rates if the feed rate is 100 kmol/s.
-The condenser duty.
-The reboiler duty.
|
Latent heat, kJ/kmol |
Heat capacity, kJ/kmol-K |
|
|
Heptane |
35,000 |
220 |
|
Ethylbenzene |
40,000 |
183 |
|
Feed temperature |
30C |
|
Condenser temperature |
95C |
|
Reboiler temperature |
99C |
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Why is mass transfer a major factor in separation processes?
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What is meant by fadding what are the factors responsible for fadding.
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Explain using manufacturers literature, how you would seal the flue?
(Gas utilisation, Level 3- Diploma in Plumbing and Heating)
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Recombinant protein is produced by a genetically engineered strain of Escherichia coli during cell growth. The recombinant protein can be considered a product of cell culture even though it is not secreted from the cells; it is synthesized in addition to normal E. coli biomass. Ammonia is used as the nitrogen source for aerobic respiration of glucose. The recombinant protein has an overall formula of CH1.55O0.31N0.25. The yield of biomass (excluding recombinant protein) from glucose is measured as 0.48 g g-1 ; the yield of recombinant protein from glucose is about 20% of that for cells.
a) How much ammonia is required?
b) What is the oxygen demand?
c) If the biomass yield remains at 0.48 g g-1 , how much different are the ammonia and oxygen requirements for wild-type E. coli that is unable to synthesize recombinant protein?
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Identify a real-world problem in which the concept of a “thin film” and an "infinite slab" can be applied and turn in a copy of an appropriate problem statement.
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Problem 1:
a. An incoming stream of 1500 lbmol/min consists of saturated water with 62% liquid water and 28% steam at 40 bar. This stream is heated at constant pressure to 700ºC. Using the steam tables, what is the heat transfer requirement for this step in kW?
b. This steam is then compressed isothermally to steam at 150 bar in a second step. What is the heat transfer requirement for this step in kW?
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Can someone tell me "what Electrochemical Factors affecting corrosion behaviour of austenitic stainless steel" ? and a general explaination for each of the factor?
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