Chemistry Questions and Answers May 08, 2020

a) Illustrate your understanding of organometallic addition chemistry by suggesting a structure for the organometallic compound (2). b) Identify the missing reagents required to convert vinyl iodide (1) into (2)

reagents TBSO (3) THP compound (2) (1) compound (4) deprotection CO,Me PGE2 compound (5) TBS THP (6)

Calculate the molarity of 6.22 10 2 mL of solution containing 20.9 g of potassium iodide.

Calculate the volume in milliliters of 2.57 M potassium hydroxide that contains 72.0 g of solute.

How many grams of solute are needed to make 923 mL of 6.89 10 2 M potassium sulfate?

a) Using 3D representations, rationalize why the deprotonation of ketone (18) with LDA gives the trans-configured enolate (19). b) Using your knowledge of Felkin-Anh control, rationalize why compound (21) has an anti stereochemical relationship between C2 and C3. c) Using 3D representations, invoke a Zimmer-Traxler structure to account for why

3 TBSO (18) OMe OTr recall that LDA is Li N. LDA OLI TBSO (19) TESO TESO OMe OTr H TBSO OTBS (21) TESO TESO (20) ...OMe OTr OTBS

Calculate the following quantity: volume in liters of 0.938 M manganese(II) sulfate that contains 60.1 g of solute.

How many moles and numbers of ions of each type are present in the following aqueous solution? Enter your answers for the numbers of ions in scientific notation. 676 mL of a solution containing 9.28 10 24 formula units of potassium bromide per liter mol potassium 10 (select) 14 16 18 20 22 24 ions potassium mol bromide 10 (select) 14 16 18 20

Calculate the molarity of sodium ion in a solution made by mixing 7.64 mL of 0.696 M sodium chloride with 500.00 mL of 8.28 10 2 M sodium sulfate. Assume volumes are additive.

Calculate the following quantity: volume of 2.07 M calcium chloride that must be diluted with water to prepare 453 mL of a 6.46 10 2 M chloride ion solution.

Ordinary household bleach is an aqueous solution of sodium hypochlorite. What is the molarity of a bleach solution that contains 40.9 g of sodium hypochlorite in a total volume of 429 mL?

If 26.1 mL of silver nitrate solution reacts with excess potassium chloride solution to yield 0.881 g of precipitate, what is the molarity of silver ion in the original solution?

The mass percent of Cl in a seawater sample is determined by titrating 25.00 mL of seawater with AgNO 3 solution, causing a precipitation reaction. An indicator is used to detect the end point, which occurs when free Ag + ion is present in solution after all the Cl has reacted. If 65.65 mL of 0.2921 M AgNO 3 is required to reach the end point,

If 36.28 mL of a standard 0.3744 M KOH solution reacts with 57.50 mL of CH 3 COOH solution, what is the molarity of the acid solution?

If 11.78 mL of a standard 0.1130 M NaOH solution is required to neutralize 36.56 mL of H 2 SO 4 , what is the molarity of the acid solution?

What will be the major product of the following reaction and what is the likely mechanism for its formation (CH)COK Br racemic OCCCH3)3 CCCH3)3 A B C D E

For the following alcohols, the order of reactivity for acidcatalyzed dehydration, from most reactive (fastest) to least reactive (slowest), will be OH Ph. Ph Ph. .CI A B C

Which of the following reagents could be used to effect the transformation shown to give the indicated alkene as the major organic product Br KO. NaOH NaOCH3 NaNH2 A B D E F A and D only A and B only any of the reagents shown C and E only O A, B, and C only O C, E, and F only

What will be the major product of the following reaction Br NaOCH3 I

c) Isotope labeling is not just about carbon Answer the following concerning H (deuterium) labeling. If you have forgotten about deuterium .. it is a stable isotope (unlike its heavier sibling.. tritium). Compounds labeled with deuterium are sometimes very useful in metabolomics .. For the following monodeuterated glucose please label any hydrogen

show and explain the mechanism with 3-nonanoic acid to y-nonanoic lactone?

Amberlyst15 heptane reflux 3nonenoic acid Ynonanoic lactone Introduction. The product of this reaction has the fragrance of coconut. order to understand the mechanism of the first step, you need to read section 23.12 and see problems 23.50 and 23.51 in McMurry (6th ed.). Amberlyst15 is a resin that serves as a source of strong acid in non aqueous

Removal of which H leads to the lowest energy (most stable) alkene product CH3 H2 Strong Base H3C. CH d. CH3 a H3 a b. of

What is most likely the first step of this reactions mechanism CH CHCH,OH Br CH3 Br CH,CH,OH CH3 Br CHCH,OH CH3 Br CH3 Br CHCH2OH

b.Heating the following compound in methanol solvent leads to a major and minor ringexpanded elimination product. Propose a mechanism for the formation of the major product, and explain why it is the major product. CH3 CH3 Br H3C CH3 CH3 CH3 CH3OH, heat major minor

Calculate the volume of water added to 0.310 L of 0.0340 M sodium hydroxide to obtain a 0.0210 M solution (assume the volumes are additive at these low concentrations).

a.When 1bromomethylcyclopentane is heated with methanol as solvent, two products are obtained Br CH3 CH2 CHOH, heat A (major) B (minor) Propose a mechanism for the formation of A, and explain why it is the major product

Calculate the following quantity: volume of 1.58 M calcium chloride that must be diluted with water to prepare 673 mL of a 6.7910 2 M chloride ion solution.

Calculate the following quantity: volume of 1.87 M calcium chloride that must be diluted with water to prepare 379 mL of a 4.60 10 2 M chloride ion solution.

Mars has a very thin atmosphere with a pressure of 610 Pa, less than 1 of the pressure found on Earth. The atmosphere on Mars is also composed of 95 CO2. Calculate the mass of CO, that would dissolve in 1.0 kg of water on Mars at 0 C. Data Henrys Law constant for CO, at 0 C is 7.28 x 102 atm 0.44 mg 0.26 mg 19 mg 0.89 mg 7.9 mg

5) Using Molecular Orbital Energy diagram, explain why the absorption maximum of methylvinylketone (A) is at 320 nm while the absorption maximum of 2methylbutadiene (B) is at 224 nm. A B.

7. 116.5 ug of trypsin (MW 23.3 kDa) was mixed in a 1 ml solution with an excess of a peptide substrate. The reaction is stopped after 10 seconds and the amount of cut peptide is measured to be 3.35 umole. The reaction is repeated with S 0.012 M, and the amount of cut peptide is measured to be 1.175 umole in 10 seconds. a) What is the

Design a series of experiments that tests increasing succinate amounts of ADP (0, 500, 750 and 1000 nmol) in the presence of no inhibitors. The curve measures oxygen consumption. Note the general shape of the curves and the endpoints of each reaction and where the lines cross the yaxis at each concentration. Write a statement that compares and

Penicillin reacts with the cysteine residue of penicillin binding protein. Show the reaction here. n

Explain the reaction and the standard gibbs free energy. The number of electron in the reaction is?

NADH is reduced below reaction QH2 12 02 Q H2O. Show AEo of this reaction.

Redraw compound 16 in your answer book and indicate clearly which bonds will be broken in step (e).

Ts N. NH NEN Ts H. 16 17

What is the reducible representation for 3 different isomers of Fe(CO)3(PPh3)2? Work needs to be shown - particularly the math for the reducible representation for all 3 isomers (plugging the numbers into the formula).

CO CO PPH3 CO PPH3 CO Fe CO PPH3 Fe Ph3PFe CO PPH3 PPH3 CO Cs C2v D3h

A flight with id LT2322 from Munich Airport (latitude 48.352179, longitude 11.781848) to Indira Gandhi Airport in New Delhi (latitude 28.555274, longitude 77.102714) has takenoff at 1200 Munich Local Time with a course on shortest distance along great circle. The average ground speed of the flight is 900 kmh. However, the flight has a serious

find a natural product which has a ketone in its structure. Describe that material on the discussion board discuss how the ketone plays a role in the activity of that natural product. Compare each others structures and they are different or the same in terms of structure and activity

A gas chromatography was used for separating a mixture that contained 3 hydrocarbons (ortho-xylene, meta-xylene, and para-xylene). Internal diameter of the column was 3.9 mm and the length was 3.6 m. Conditions of the first trial are: Room pressure = 695.1 mm Hg Room temperature = 23.0 o C Inlet pressure = 65.0 psi Column temperature = 350 o C He

20

Provide a mechanism for the following transformation (the unit is on nonclassical carbocations and substitution reactions).

POTS NO H. OH H. H. OH

Lake Operon has a surface area of 5.5 X 10 8 m2 . There is a stream that flows in to the lake with a phosphorus concentration of 25 g/L and a flow rate of 75 m3 /s. The phosphorus settling rate (vs) within the lake is 8 m/yr. Assume the incoming stream has the same flow rate as an outgoing stream and that settling occurs over the entire lake.

What is the atmospheric rate constant of ethane and ethene? (show rate constant procedure)

What is the most likely molecular geometry of the complex Fe(en)2CI2 O trigonal planar O octahedral O tetrahedral or square planar O linear O bent

Calamine, which is used for the relief of skin irritations, is a mixture of zinc and iron oxides. A 1.022-g sample of dried calamine was dissolved in acid and diluted to 250.0 mL. Potassium fluoride was added to a 10.00-mL aliquot of the diluted solution to mask the iron; after suitable adjustment of the pH, Zn 2+ consumed 38.71 mL of 0.01294 M

Fe3 ZnY2 FeY Zn2

Calamine, which is used for relief of skin irritations, is a mixture of zinc and iron oxides. A 1.022g sample of dried calamine was dissolved in acid and diluted to 250.0 mL. Potassium fluoride was added to a 10.00mL aliquot of the diluted solution to mask the iron after suitable adjustment of the pH, Zn2 consumed 38.71 mL of 0.01294 M EDTA. A

Mushrooms that dont brown, wheat that fights off disease, tomatoes with a longer growing season, all of these crops are made possible by a geneediting technology called Crisprcas9. Explain THREE (3) possible risks in which genetically modified food could cause to the society.

Which of the following statements are true Check all that apply. In fluorescence, AS 0. The rate of fluorescence is higher than that for phosphorescence. Fluorescence is a forbidden transition. O In phosphorescence, AS 0. Apparently the answers are not just option 1 and 2.

Co(OH)2 5.92x1015 CuBr 6.27x109 CuCO3 1.4x1010 Fe(OH)2 4.87x1017 PBCO3 7.40x1014 PbCrO4 2.8x1013 PBF2 3.3x108 Mg(OH)2 5.61x1012 Ni(OH)2 5.48x1016 AgBrO3 5.38x105 Ag2CO3 8.46x1012 AgCI 1.77x1010 Ag2CrO4 1.12x1012 SrCO3 5.60x1010 ZnCO3 1.46x1010 Zn(OH)2 3.0x1017 AgBr 5.35x1013 AuCI 1.77x1010 ,Calculate the solubility at 25 C of PbCrO, in pure water

Initialy, only A and B are present, each at 2.00 M. What is the final concentration of A once equilibrium is reached Express your answer to two significant figures and include the appropriate units. ,Part B What is the final concentration of D at equilibrium if the initial concentrations are A 1.00 M and B 2.00 M 3D Express your answer to two

According to Bronsted and Lowry, which one of the following is not a conjugate acid-base pair? A. H 3 O + /OH B. CH 3 OH 2 + /CH 3 OH C. HI/I D. HSO 4 /SO 4 2 E. H 2 /H

In the following equation, identify the acids, bases, and conjugate pairs. NH 4 + + BrO 3 NH 3 + HBrO 3 (a) What is the acid? NH 4 + BrO 3 NH 3 HBrO 3 (b) What is its conjugate base? NH 4 + BrO 3 NH 3 HBrO 3 (c) What is the base? NH 4 + BrO 3 NH 3 HBrO 3 (d) What is its conjugate acid? NH 4 + BrO 3 NH 3 HBrO 3

A 0.150 M sodium chloride solution is referred to as a physiological saline solution because it has the same concentration of salts as normal human blood. Calculate the mass of solute needed to prepare 275.0 mL of a physiological saline solution.

In the following reaction, what ions, if any, are spectator ions? Pb(NO 3 ) 2 ( aq ) + 2NaCl( aq ) PbCl 2 ( s ) + 2NaNO 3 ( aq )

Magnesium carbonate, MgCO 3 , is insoluble. Identify the spectator ions when aqueous solutions of sodium carbonate and magnesium chloride are combined. A. Mg 2+ and CO 3 2 B. Na + and Cl C. Mg 2+ and Cl D. Na + and CO 3 2 E. None of these choices are correct.

Select the precipitate that forms when the following reactants are mixed. Na 2 CO 3 ( aq ) + BaCl 2 ( aq ) A. Ba 2 CO 3 B. BaCO 3 C. NaCl D. NaCl 2 E. BaO

Which of the following precipitate that forms when aqueous ammonium sulfide reacts with aqueous copper(II) nitrate. A. CuS B. Cu 2 S C. NH 4 NO 3 D. NH 4 (NO 3 ) 2 E. CuSO 4

Select the correct name and chemical formula for the precipitate that forms when the following reactants are mixed. CuCl 2 ( aq ) + Na 2 CO 3 ( aq )

Select the net ionic equation for the reaction between sodium chloride and mercury(I) nitrate. 2NaCl( aq ) + Hg 2 (NO 3 ) 2 ( aq ) 2NaNO 3 ( aq ) + Hg 2 Cl 2 ( s ) A. Na + ( aq ) + NO 3 ( aq ) NaNO 3 ( aq ) B. Hg 2 2+ ( aq ) + 2Cl ( aq ) Hg 2 Cl 2 (s) C. NaCl( aq ) Na + ( aq ) + Cl ( aq ) D. Hg 2 (NO 3 ) 2 ( aq ) Hg 2 2+ ( aq ) + 2NO 3 (

Consider the reaction: 3Co 2+ ( aq ) + 6NO 3 ( aq ) + 6Na + ( aq ) + 2PO 4 3 ( aq ) Co 3 (PO 4 ) 2 ( s ) + 6Na + ( aq ) + 6NO 3 ( aq ) Identify the net ionic equation for this reaction. A. Na + ( aq ) + NO 3 ( aq ) NaNO 3 ( aq ) B. 3Co 2+ ( aq ) + NO 3 ( aq ) + Na + ( aq ) + 2PO 4 3 ( aq ) Co 3 (PO 4 ) 2 ( s ) + NaNO 3 ( aq ) C. 3Co 2+ ( aq )

Categorize each of the following ionic compounds as soluble or insoluble in water. 1. CaCO3 2. BaSO4 3. PbBr2 4. Ca(C2H3O2)2 5. PbS 6. PbF2 7. AgCI 8. Fe(OH)2 9. Na2CO3 10. Ag2SO4 11. KCI 12. LiOH 13. (NH4)2S 14. NaNO3 15. (NH4)SO4

Classify each given species as a strong acid, weak acid, strong base or weak base. 1. CH3COOH 2. LiOH 3. HF 4. NH3 5. H3PO4 6. H2SO4 7.Ca(OH)2 8. HCIO4 9. HBr 10. Ba(OH)2 11. NaOH 12. Sr(OH)2 13. HNO3 14. HCI 15. KOH

Calculate the number of grams of solute in 278.4 mL of 0.208 M calcium acetate.

Calculate the molarity of 3.53 10 2 mL of solution containing 16.0 g of potassium iodide.

Calculate the number of moles of solute in 307.3 L of 0.990 M sodium cyanide.

Calculate the volume in milliliters of 2.04 M potassium hydroxide that contains 58.5 g of solute.

Calculate the following quantity: molarity of a solution prepared by diluting 43.33 mL of 0.0253 M ammonium sulfate to 475.00 mL.

Calculate the following quantity: final volume of a 0.0154 M solution prepared by diluting 17.6 mL of 0.168 M lithium carbonate with water.

An Acid... A. produces hydroxide ions when dissolved in water. B. changes the color of phenolphthalein indicator from colorless to pink. C. donates electrons in an electron transfer reaction. D. donates protons in a proton transfer reaction. E. None of these choices are correct.

Complete the following acid-base reaction with balanced molecular, total ionic, and net ionic equations. Be sure to include states of matter in your answer. calcium hydroxide( aq ) + acetic acid( aq ) Molecular: Total ionic: Reactants Products Net ionic:

Tem took 1.00 ml of seawater and diluted it to 125.00 ml of distilled water. He titrated the sample with 0.004501 M EDTA. It took 15.25 mL of 0.004501 M EDTA to reach endpoint. What is the ppm CaCO3 of his water sample MW of CaCO3 100.09 gmole. 1000 mg 1 gram (5 3D 100.095

Using appropriate diagrams, explain the different types of tacticity that can be exhibited by the polymer when racemic Bbutyrolactone (racBBL) is polymerised catalytically. Explain how the behaviour of the catalyst determines the tacticity of the polymer obtained. racBBL

For each of the following questions, give a short explanation (23 sentences). You may include equations to assist your explanation. a. In solid state catalysis, what is the mechanistic difference between the Langmuir Hinshelwood and the RidealEley mechanism b. In gas phase reactions, why are unimolecular reactions observed to show second order

a) Why is potassium iodide to your flasks after a reaction with the Wijs reagent? b) Draw the reaction illustrating the hydrolysis of p-nitrophenyl dodecanoate by lipase. Specifically show what the reactants and the products are. c) Why is starch used as an indicator in titrations? Why is it added to a flask?

a) Compounds 1-3 are three of the most potent fragments from a recent screening study. For each compound, state the number of hydrogen bond donors and hydrogen bond acceptors. (3 marks) b) Based on your donor/acceptor counts, briefly comment on the reliability of rules such as the Rule of Three. (1 mark) c) What molecular property is LogP a

NH2 1 3

i) The following compound 6 is a fragment that was synthesized from 4 via an epoxide 5. What reagents could achieve the reaction to form 5, and explain the observed stereoselectivity? (2 marks) ii) The formation of 6 from 5 is achieved using hydrazine (H 2 NNH 2 ) in acetic acid. Like the Shapiro reaction, the reaction goes through a vinyl anion

OH OH H2NNH2 ACOH 5 6

a) By consideration of the reactivities of the carbonyl groups of the dione and the amino groups of the hydrazine, explain why regioisomer 7 is the main reaction product. (3 marks) b) Provide a mechanism for the above reaction to give 7; the aryl groups may be abbreviated as Ar and Ar.

NH, H,C cat. HCI NN H,C ethanol (solvent) heat HNSo

i) Apply Lipinskis Rules to the structure of indinavir. (4 marks) ii) What does your Lipinski analysis tell you about the suitability of indinavir as a drug? Briefly explain the limitations of this analysis. (2 marks)

N. OH OH Indinavir 1 Molecular Weight 613.80 logP 2.49 IZ ZI

i) Suggest a reason why this might be considered a good point for a first disconnection.? ii) Fragments 14 and 15 could be connected through an amide bond formation using DCC and a base (NEt 3 ) as the reagents. Provide a mechanism for this reaction. (Hint: Use the general structures R1 -NH2 and R2 -CO2H to save drawing out the full structures.) ?

HN H HN HN HN HN NHAN NHHN 14 NH OH 13 1o0oo. HO DCC, NET OMOM 15 NH NH NBoc NHBoc NCN om DCC

a) Apply Lipinskis Rules to the structure of lamivudine. (4 marks) b) What does your Lipinski analysis tell you about the suitability of lamivudine as a drug? What are the limitations of this analysis? (2 marks) c) By comparing the structure of lamivudine 1 to cytosine deoxyribonucleotide 2, explain briefly how this drug might inhibit reverse

NH2 NH HO HO H Lamivudine 1 Cytosine deoxyribonucleotide 2 Molecular Weight 229.25 LogP 1.4

i) Genome mining involves a combination of genomics, bioinformatics, molecular biology and analytical chemistry. Briefly outline what takes place at each of these steps in the process. (4 marks) ii) What are the general features of a pleiotropic approach to activating a silent biosynthetic gene cluster (BGC)? Briefly outline the main advantage and

The payoff matrix for a game is given by 2 4 4 3 Compute the expected payoffs of the game for the pairs of strategies in parts (ad). (Round your answers to one decimal place.) 0, e (a) P E (b) P 0 1 E 1 (c) 1 P 1 Q 2 2 E 0.5 (d) P 0.9 0.1 Q 0.5 E Which of these pairs of strategies is most advantageous to R O (a) O (b) O (c) O (d)

3. Which compound below would be least likely to undergo a substitution reaction with NaOEtEIOH (A) ethanoyl chloride (B) acetone (C) bromoethane (D) acetic anhydride (E) phenyl acetate

4. Borneol is a chiral organic compound that acts as a natural insect repellent. A levorotatory mixture consisting of 68 (borneol and 32 ()borneol has (alo 13. What is the specific rotation, ajo of ()borneol Please show your work below.

A 50.0 mL sample containing Cd2+ and Mn2+ was treated with 65.1 mL of 0.0400 M EDTA. Titration of the excess unreacted EDTA required 15.0 mL of 0.0190 M Ca2+. The Cd2+ was displaced from EDTA by the addition of an excess of CN. Titration of the newly freed EDTA required 22.7 mL of 0.0190 M Ca2+. What are the concentrations of Cd2+ and Mn2+in the

Relationship between the reaction quotient and the equilibrium constant The equilibrium concentration of each component depends on the initial conditions, the direction in which the reaction proceeds to attain equilibrium, and the magnitude of the K value. If K Q for the initial concentrations, the net reaction will proceed forward to produce

78 The chiral Mn complex below undergoes racemization according to the equation shown. Mn PhMe25 C PPH3 PPH3 Ph3P NO NO NO Ph t12 21 min. 1PPh3 Ph Ph Rate x Propose a mechanism that is consistent with the rate being affected inversely by the concentration of PPh.

Given the two reactants what is the product and what mechanism occurs?

Br NA reflUX 7