For the reaction shown below, circle the solvent (MeOH, CHCl3, DMF) that results in the fastest reaction rate. Briefly explain your choice. 5 points for correct choice, 5 points for explanation.

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Turn off all electronic devices before the exam. During the exam, you are permitted: a molecular model kit and two 8½ in. × 11 in. sheets of handwritten notes. (Front and back; no typed or electronic notes!) Stencils for drawing conformations are not permitted. Put your name on every page in case your exam packet is disassembled during the grading process. The use of blue or black ink (rather than pencil) is strongly encouraged. Please let me or the TAs know if you need additional sheets of scrap paper.

Q1 (50 pts., 10 pts. each) Provide a short response and/or a brief explanation for each of the questions below. Use no more than three (3) sentences and one (1) drawing for an explanation. An excessively long response may be penalized even if it is correct.

(a) Using dash-wedge notation, draw all stereoisomers of the molecule shown below. Show each stereoisomer only once. Give the total number of stereoisomers in the box provided. 2 points for every non-repeated stereoisomer shown. 4 points for correct number of stereoisomers.

(b) Assign (R) or (S) for all stereocenters in the two structures shown below. State the relationship between the structures. Are they different depictions of the same molecule, enantiomers, or diastereomers? 1.5 points each for (R)/(S) assignment. 4 points for correct relationship.

(c) For the reaction shown below, circle the solvent (MeOH, CHCl3, DMF) that results in the fastest reaction rate. Briefly explain your choice. 5 points for correct choice, 5 points for explanation.

(d) An enterprising, self-employed chemist (who isn’t nearly as good as Walter White) prepared a batch of N-methyl-1-phenylpropan-2-ammonium chloride with [α]D25 = +8. The Merck Index indicates that [α]D25 = +20 for a pure sample of the (S) isomer.1 What is the percent enantiomeric excess (% e.e.) of the product? The enantiomer excess is 8/20, or, as a percentage, 40% e.e. 7 points if division is shown, but not converted to a percentage.

(e) Predict the product(s) of the following substitution reaction. Be sure to show all stereoisomers formed. (Note: When predicting the product, show only the stable organic product(s) formed at the end of the reaction. Do not show any reactive intermediates involved in the mechanism.)

5 points if only one diastereomer is shown. No credit for showing carbocation or an incorrect Lewis structure. 5 point deduction for showing products that are still protonated.

1 The pure (S) isomer would make his customers happy. The (R) isomer has different biological properties, acting mainly as a nasal decongestant.

 

Q2 (50 pts., 10 pts. each) For each of the subproblems below, choose the faster reaction by circling it. For each pair of reactions you are comparing, assume that all other reaction conditions that are not explicitly shown (e.g., reagent concentration, temperature, etc.) are the same for both reactions. You do not have to explain your choice.

(a) Beta branching slows down SN2 reactions.

(b) SN2 reaction; heavier element in same column is more nucleophilic.

(c) Secondary (benzylic) carbocation forms more readily in SN1 reaction.

(d)SN2 reaction; iodide is better leaving group.

(e) SN2 reaction is faster in polar aprotic solvents like acetone.

 

Q3 (50 pts.) Answer the following questions about structures A − C, shown below. For this question, you may assume that we are operating at temperatures at which chair flips occur rapidly.

(a) (30 pts.) For each of A, B, and C, state whether the molecule is chiral or achiral.

A: achiral

B: chiral

C: chiral

10 points for each correct statement.

(b) (10 pts.) State the relationship between B and C. Are they different depictions of the same molecule, enantiomers, or diastereomers? (Think carefully before you (c) (10 pts.) Draw one molecule that is a diastereomer of A, B, C, and Cʹ.

Q4 (50 pts.) The molecules menthol and isomenthol are depicted below.

(a) (40 pts.) Draw the two chair conformations of each compound.

8 points for each correct chair. 4 points for each correct conformer circled.

(b) (10 pts.) Based on the conformations available to these two molecules, which compound is more stable, menthol or isomenthol? Give a one sentence justification.

 

Extra credit (15 pts., 5 pts. each).

(a) Racemic omeprazole (Prilosec) is a proton pump inhibitor used to treat heartburn. Circle the stereocenter in this molecule.

(b) (S)-Omeprazole (“esomeprazole”, Nexium) is the newer version of the drug. Draw the structure of this molecule with the appropriate stereochemistry indicated.

(c) (Continuation of Q1d): In a 10 g sample of the product he made, how many grams each of the (R) and (S) isomers are present?

 

 

Defining the concepts, theories and approaches of project management. Analyze to work effectively and efficiently as a team member for project related cases.

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Project Management

Assignment Purposes/Learning Outcomes:

After completion of Assignment-2 students will able to understand the

  1. Defining the concepts, theories and approaches of project management. (L.O-1.1)
  2. Analyze to work effectively and efficiently as a team member for project related cases. (L.O-3.1)
  3. Evaluate to monitor and control the project. (L.O-3.2)

 

 Assignment-2: Case Study & Discussion questions

Assignment Case study Question:            (Marks 9)

Read the Case-8.3 “Tham Luang Cave Rescue.”  from Chapter 8 “Scheduling Resources and Costs” given in your textbook – Project Management: The Managerial Process 8th edition by Larson and Gray page no: 304-307 also refer to specific concepts you have learned from the chapter to support your answers.  Answer the following questions for Part-1, Part-2.

 

Part-1: Case study questions

  1. How did the physical environment of the cave affect the rescue plan? Explain in 250 words(3 Marks).
  2. How did the rescue team respond to the risks of the project? Explain in 250 words (3 Marks).
  3. Some have called the rescue a miracle and that luck was the decisive factor. Do you agree? Explain in 150 words (3 Marks)

 

Part-2: Discussion questions

Read Chapter 8 Pg-No. 279 & 281 carefully and then give your answers on the basis of your understanding.

  1. Why would people resist a multi project resource scheduling system? (3 Marks) (200 words)
  2. What do you think would have happened if the Washington Forest Service did not assess the impact of resources on their two-year plan? (3 Marks) (200 words).

Answers:

 

90 gram of H2O contains how many moles?

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Chemistry
90 gram of H2O contains how many moles?

How many ions are formed during the dissociation of 500 molecules of carbonic acid, if it dissociates in the first degree by 20%, and in the second degree by 1%? Explain your answer.

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Dissociation of 500 molecules of carbonic acid

How many ions are formed during the dissociation of 500 molecules of carbonic acid, if it dissociates in the first degree by 20%, and in the second degree by 1%? Explain your answer.

 

What is the total volume of gaseous products formed when 38.6 liters of propane (C3H8) react completely according to the following reaction? How many moles of hydrochloric acid are needed to produce 6.54 L of chlorine gas according to the following reaction at 0 °C and 1 atm?

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1)Nitrogen monoxide is a pollutant commonly found in smokestack emissions. One way to remove it is to react it with ammonia.

4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(ℓ)

How many liters of ammonia are required to change 17.2 L of nitrogen monoxide to nitrogen gas? Assume 100% yield and that all gases are measured at the same temperature and pressure.

 

2) What is the total volume of gaseous products formed when 38.6 liters of propane (C3H8) react completely according to the following reaction? (All gases are at the same temperature and pressure.)

Propane (C3H8)(g) + oxygen (g) → carbon dioxide(g) + water (g)

Volume =  L

 

3) How many moles of hydrochloric acid are needed to produce 6.54 L of chlorine gas according to the following reaction at 0 °C and 1 atm?

Amount =  moles

 

4) How many grams of calcium carbonate are needed to produce 5.20 L of carbon dioxide according to the following reaction at 25 °C and 1 atm?

 

calcium carbonate (s)   calcium oxide  (s) + carbon dioxide (g)

 

g calcium carbonate

 

5) What volume of carbon dioxide is produced when 21.3 g of calcium carbonate reacts completely according to the following reaction at 25 °C and 1 atm?

calcium carbonate (s) → calcium oxide(s) + carbon dioxide(g)

Volume =  L

 

 

 

6) Sulfur trioxide, SO3, is produced in enormous quantities each year for use in the synthesis of sulfuric acid.

S(s) + O2(g) → SO2(g)

2SO2(g) + O2(g) → 2SO3(g)

What volume of O2(g) at 340.°С and a pressure of 5.25 atm is needed to completely convert 4.50 g sulfur to sulfur trioxide?

Volume =  L

 

7) An important process for the production of acrylonitrile (C3H3N) is given by the following equation:

2C3H6(g) + 2NH3(g) + 3O2(g) → 2C3H3N(g) + 6H2O(g)

A 120.-L reactor is charged to the following partial pressures at 24°C:

PC3H = 0.340 MPa

PNH3 = 0.890 MPa

PO2 = 1.400 MPa

What mass of acrylonitrile can be produced from this mixture ()?

Mass =  g

 

8) A 20.0-L nickel container was charged with 0.821 atm of xenon gas and 1.17 atm of fluorine gas at 400°C. The xenon and fluorine react to form xenon tetrafluoride. What mass (g) of xenon tetrafluoride can be produced assuming 100% yield?

g XeF4

 

9) Consider the unbalanced chemical equation below:

CaSiO3(s) + HF(g) → CaF2(aq) + SiF4(g) + H2O(l)

Suppose a 30.9 g sample of CaSiO3 is reacted with 32.3 L of HF at 27.0 °C and 1.00 atm. Assuming the reaction goes to completion, calculate the mass (in grams) of the SiF4 and H2O produced in the reaction.

mass SiF4 =  g

mass H2O =  g

 

 

10) A sample of a gas mixture contains the following quantities of three gases.

compound mass
CO 2.46 g
CO2 1.55 g
SF6 3.90 g

The sample has:

volume = 2.50 L

temperature = 16.6 °C

What is the partial pressure for each gas, in mmHg?

What is the total pressure in the flask?

CO  mmHg

CO2  mmHg

SF6  mmHg

total  mmHg

 

11) A mixture of xenon and helium gases is maintained in a 7.73 L flask at a pressure of 1.28 atm and a temperature of 51 °C. If the gas mixture contains 18.1 grams of xenon, the number of grams of helium in the mixture is  g.

What is the structure, traditional name and IUPAC name of the molecule? Provide a picture from the web or draw by hand or with a program. What does the compound/molecule do in each enantiomeric form?

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Escitalopram (Lexapro) vs. Citalopram (Celexa)

Choose ONE of the following topics and write a 4-5 page paper (minimum) with citations in MLA or APA format. Please use 12 point font, 1 inch margins. Address in your paper the following:
a. What is the structure, traditional name and IUPAC name of the molecule? Provide a picture from the web (citation required) or draw by hand or with a program.
b. Label your molecular drawing(s) with the CIP rankings and indicate the R or S assignment for each chiral center.
c. What does the compound/molecule do in each enantiomeric form?
d. Why is drug/molecule chirality important?
e. Where is the important chiral center(s)?
f. What health effects if any are of concern?
g. Is it possible to separate the enantiomers to make a single enantiomer drug?

Where is there a higher concentration of dissolved particles: inside or outside of the cell? Where is there a higher concentration of water: inside or outside of the cell? Which direction will water flow: into or out of the cell?

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DEMONSTRATE YOUR UNDERSTANDING OF OSMOLARITY

1. DRAW a picture of a cell placed in a hypotonic solution that shows the relative amount of dissolved particles (e.g. salt) in the cell vs. in the solution.
a. Where is there a higher concentration of dissolved particles: inside or outside of the cell? .
b. Where is there a higher concentration of water: inside or outside of the cell?
c. What flows into/out of the cell: water or dissolved particles such as salt (Na+ Cl-)?
d. Which direction will water flow: into or out of the cell? .
e. What will happen to an animal cell placed in this solution?
f. Will a plant cell placed in this solution lose or gain weight, and why?

2. DRAW a picture of a cell placed in a hypertonic solution that shows the relative amount of dissolved particles (e.g. salt) in the cell vs. in the solution.
a. Where is there a higher concentration of dissolved particles: inside or outside of the cell?
b. Where is there a higher concentration of water: inside or outside of the cell? .
c. What flows into/out of the cell: water or dissolved particles such as salt (Na+ Cl-)?
d. Which direction will water flow: into or out of the cell? .
e. What will happen to an animal cell placed in this solution?
f. Will a plant cell placed in this solution lose or gain weight, and why?

3. DRAW a picture of a cell placed in an isotonic solution that shows the relative amount of dissolved particles (e.g. salt) in the cell vs. in the solution.
a. Compare the concentration of dissolved particles on the inside and outside of the cell .
b. Do you expect water to flow into or out of the cell? Explain .
c. What will happen to an animal cell placed in this solution?.
d. Why will a plant cell placed in this solution neither lose or gain weight? .

If the average annual particulate concentration in the city is 57 ug/m3, what is the annual quantity of pollutants discharged into the air above the City of A?

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Assignment #1

Round answers to an appropriate number of digits and include proper units.

A labelled diagram is required for each question.

Answer the following problems, providing details on all calculations. The #, ##, ### or #### will represent the LAST 1,2,3 or 4 digits of your student number. 000837359

Question 1) Air Pollution Mass Balance 

The City of A is approximately 25 km (width) by 40 km (length). The average wind speed is 15 kph from the northwest and flows through an altitude of approximately 1 km. If the average annual particulate concentration in the city is 57 ug/m3, what is the annual quantity of pollutants discharged into the air above the City of A? (Report final answer in tonnes per year) Assume the concentration of particulates coming into Hamilton is ‘0’; and accumulation of particulates is 37359 kg/d. Use a block diagram to illustrate your work.

Question 2) Dissolved Oxygen in Water

An industrial WWTP discharges into a large river 0.42 m3/s of industrial effluent with an ultimate BOD concentration of 273 mg/L and a D.O. concentration of 1.9 mg/L at a temperature of 20∘C. The velocity of the river is 0.75 m/s. Upstream of the point of discharge, the river has a temperature of 8∘C, an ultimate BOD of 17 mg/L and a flow rate of 5.1 m3/s. Use a diagram to illustrate the problem. State all assumptions.

Calculate:

  • the DO concentration at the point of discharge
  • the DO deficit at the point of discharge
  • the ultimate BOD at the point of discharge

Identify and address the current problems with inventory shrinkage. Select and discuss one of the following internal controls below you would implement to help prevent future employee fraud/theft? Provide your rationale.

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Analytical Chemistry

Part 1: Post a Response

View this short introduction to the discussion.

Click here to watch the video

According to a recent article from Forbes, retail operations in the United States are experiencing over $60 billion a year in losses primarily due to employee theft.

Imagine you have been hired as a loss prevention specialist for a large retail chain and your first assignment is to identify and address the current problems with inventory shrinkage. Select and discuss one of the following internal controls below you would implement to help prevent future employee fraud/theft? Be sure to provide your rationale.

  • Option A: More stringent background screenings for new hires (i.e. reference checks, criminal record checks, credit record checks)
  • Option B: Tighter security controls (i.e. video surveillance, random inventory/cash audits, computer system audits, segregation of duties)

Part 2: Respond to a Peer

Read a post by one of your peers and respond, making sure to extend the conversation by asking questions, offering rich ideas, or sharing personal connections.

Reference Article

 

Convert mass of calcium carbonate to moles of calcium carbonate. Compare moles of calcium carbonate to moles of sodium carbonate based on balanced equation to calculate moles of sodium carbonate required.

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Lab Report #10 Synthesis of Calcium Carbonate

Questions
Order the steps required to predict the volume (in mL) of 0.100 M sodium carbonate needed to produce 1.00 g of calcium carbonate. There is an excess of calcium chloride.

Step 1 : Convert mass of calcium carbonate to moles of calcium carbonate.
Step 2 : Compare moles of calcium carbonate to moles of sodium carbonate based on balanced equation to calculate moles of sodium carbonate required.
Step 3 : Compute the volume of sodium carbonate solution required.
Step 4 : Convert the volume of sodium carbonate solution required from liters to milliliters.  Calculate the volume (in mL) of 0.100