Chemistry Questions and Answers June 12, 2020

The following Potential Energy (PE) curves indicate the formation of a single bond and triple bond (not necessary in that order) between two identical atoms. Curve A represents the formation of a bond as is evident from the v in bond strength. Distance between atoms Distance between atoms

Suggest to the chemical company on the type of separator that able to achieve 99% purity of ethanol at the end of the separation process (Feed: mixture of 40% ethanol and 60% water). Support your suggestion with VLE data and other relevant information.

For the honours project, a student synthesized a poly(vinyl chloride) (PVC) by solution polymerization at 60 C as shown in the following scheme. to Benzoyl Peroxide H2C CH 60 C CI Vinyl chloride Polyvinyl chloride (PVC) The concentrations of vinyl chloride and benzoyl peroxide that the student used were 8.462 mol.dm3 and 3.336 x 103 mol.dm3

What is the halflife of methane in the atmosphere in years at 315 K (Assume that CH403AO4.95x107M). Explore what a halflife of methane means in the reaction and comment on the consequence of that in the atmosphere.

A 50.00-mL solution containing NaBr was treated with excess AgNO3 to precipitate 0.2146 g of AgBr (187.772 g/mol). What is the molarity of NaBr in the solution?

1. Flood the starch agar plate with the lodine solution, allow the iodine to remain in contact with the medium for 30 seconds, and pour off the excess. 2. Examine the cultures for the presence or absence of a blueblack color surrounding the growth of each test organism. Describe the Appearance of the medium around the cells Result ( or ) for

A 0.1070 g rock sample containing an unknown amount of Ca was dissolved in HCl and diluted to 100.0 mL. Aliquots of 20.00 mL from this solution were added to different volumes of a 2.08 ugmL Ca standard solution and diluted to 200.0 mL. The emission intensity of these solutions was measured using atomic emission spectroscopy. The results are shown

Figure 2 shows the steps involved to confirm the presence of anion and cation in solid lead (II) carbonate. Using the reagents provided, describe the methods used to confirm the presence of ions and observations involved. Lead (II) carbonate Reagents Sodium hydroxide solution, ammonia solution, nitric acid, sulphuric acid, lime water Apparatus

A hot cylinder ingot of 50 mm diameter and 200 mm long is taken out from the furnace at 800C and dipped in water until its temperature falls to 500C. Then it is directly exposed to air until its temperature falls to 100C. The properties are ha (heat transfer coefficient in air 20Wm2C), hw (heat transfer coefficient in water 200Wm2C), kingot 60 Wm

A 0.1 M solution of a weak acid (HA) has a pH 2.40. 3D a) What is the Ka of the weak acid Show your work b) What is the pOH of this solution Given HA(aq) H,O(1) H,O(aq) A (aq) Your solution shall include Areaction table 4 points Finding H30 4 points Finding Ka 4 points Checking the assumption 4 points Finding pOH 4 points

Consider the following spectroscopic data for the identification of an organic intermediate for the synthesis of a 1,3,4-oxadiazole. The mass spectrum shows a molecular ion at 157 m/z, with an M+1 peak at about 7.42% of the molecular ion. There is also an M+2 peak with an abundance that is ~32% of the molecular ion. Provide the structure of this

8 100 90 80 70 60 50 40 30 20 10 240 220 200 180 160 140 120 100 60 60 40 20 157 158 amu 161 162 159 160 Abundance Information Gleaned m2 157 100 7.42 158 159 32.02

Use the following template DNA to determine the mRNA and peptide sequence that will form. DNA 3ATACCGTCG5 MRNA (be sure to show the 3 and 5) A Amino acid (use oneletter abbreviations)

5. Provide a stepwise synthesis for the following. H. 6. Draw all of the resonance structures of the sigma complex which is formed when benzene reacts with an electrophile (E).

Aqueous copper (I) sulphate is mixed with aqueous strontium bromide, what's complete and net ionic equations.

explain more in detail to understand this graph

reduction F190.019 EX coeft20.pps 40 SW11497 PW 22.30 PO 10 MC OF15339 NAI 36 LB00 PPM USER DLLDATE 042720 (1002) Notkomp PTS14 8192

1. For each ruler diagram below,(a) state the decimal place (tens, ones, tenths, etc.) of the smallest intervals marked on the ruler, (b) state the decimal place which the measurement should be reported to, and (c) give a reasonable value for each point indicated on the diagram. Since no units are indicated, do not write any on this problem set.

1. The absorption spectrum of aqueous CoCl Wavelength (nm) Wavelength (nm) A Wavelength (nm) 0,057 400 0.623 0.809 D. 785 475 550 425 0.134 D.128 0.066 500 575 D.362 450 525 600 The maximum absorbance occurs at 0O nm. 2. The absorbance as a function of the concentration (c) Wavelength to be used for measurements 0 nm Test Tube No. 0.804 1 0.620

Given the going with molecule of DNA: strand 1 A T G C G C T A C G C A T strand 2 T A C G C G A T G C G T A Determine the mRNA molecule, the tRNA anticodons, and the amino destructive game plan that will be conveyed if strand 1 is the record design for the mRNA particle.

Which molecule, shown below, matches the following IR spectrum L00 4000 3000 1000 NEVENUBERIl

Starting with 10.00 mL of solutions AE, presented in question 3, 1.00 mL of 0.10 M HCI is added to each of them. Determine the new pH of the solutions. Ammoniums pk 9.30. Give your answers to two decimal places. 3D Mixture pH 8.35 10.00 mL A 1.00 mL HCI 7.30 10.00 mL B 1.00 mL HCI 9.50 10.00 mL C 1.00 mL HCI 9.32 10.00 mL D 1.00 mL HCI 11.70

Find the Theoretical Yield of 9,10dihydroanthracene9,10a,succinic acid anhydride in MOLES Maleic acid 1.082 g molecular weight98.06 gmol Anthracene2.0835 g molecular weight178.23 gmol 9,10dihydroanthracene9,10a,succinic acid anhydride molecular weight 276.29 gmol

The function of a heat pump is to draw energy from a low temperature source such as the cold winter air and deliver it to a region of higher temperature such as the interior of a house. In terms of the diagram, the efficiency of a heat pump is measured by the ratio of the energy delivered to the higher temperature, Q., to the work, W. required to

Al 20C, a 1.14 M aqueous solution of ammonium chioride has a density of 1.0168 gimt. What is the molality of ammonium chioride in the solution The formula weight of NH,CI is 53.50 gmol. O 1.19 m

1. a) (10 pts) Name the following compounds. OH i) ii) iii) iv) v) OH

For the graph, present the kinetic energy distributions at the two extreme temperatures. Propose a correlation between thermal order and entropy.

Relative Number Translat. Kinetic Energy Distribution 40 Kinetic Energy (3)

Suggest a suitable mechanism for the following organic reactions

Ph Ph N. Ph Ph N triisopropylbenzene N. Ph N. Ph N. Phi N. CH3 27 232 C, 36 h 70 CH3

Suggest a suitable mechanism for the following organic reactions

CN CN 1. 4 eq. NaHMDS, 30 to 15 C tBuMe2Si tBuMe2SiO Ph Ph 2. PhCH2Br, 10 C, 75 ben zel broni el Ph

If 250.0 ml of 0.7500 M sulfurous acid at 25.0 E is mixed with 300.0 mL. of 0.7500 M ammonium hydroxide, also at 25.0 E. what will the final temperature reached by the resulting solution AHnn 102.1 kJmol.

Draw a complete mechanism of the following reaction.

Me 1 Me,SO4, aq. NaOH 2 NaOH, H,O EtO N. HO N. Pr Pr 2 3 IZ

Draw the mechanism for the following reaction

Me 1 Me,SO4, aq. NaOH 2 NaOH, H,O EtO N. HO N. Pr Pr 2 3 IZ

Question 1 CuAu (CopperGold) binary alloy crystal consists of N Cu atoms and N Au atoms. The structure can be modelled as follows. At T OK perfectly ordered system has N Cusites occupied by N Cu atoms, and N Ausites occupied by N Au atoms. At a finite temperature T, n Cu atoms are displaced to Ausites, and n Au atoms are displaced to Cusites. For

(1) Draw the structure of Mn(CO)3(C5H5) What is the hapticity of the CsIs ligand What is the charge of the CSH5 ligand For the complex, predict the number of CO stretches in the IR spectrum. Explain the shifts of the CO peaks in the IR spectrum when the CsHs ligand is replaced with C5Mes. (11) (I) (1) (iv) (v)

Explain any 3 factors that affect the leaching from waste material.

Approximately how many times faster or slower is the average reaction rate during the first four seconds (t = 0 to t = 4) than the second four seconds (t = 4 to t = 8) for the following reaction? 2NOBr(g) Br2(g) + 2 NO(g)

Explain and solve the equation that explains the temperature deviation of a spherical gas cloud in mutual magnetism of its molecules and subject to the laws of thermodynamics.

Below is the mechanism for Enzyme X, which uses compound A as a cofactor: What catalytic mechanism(s) is the cofactor A using (consider all the steps)? What is the purpose of each mechanism (be specific on each purpose-what does the cofactor A do and how it makes the reaction go faster)?

CH, CH, HN HN HO OH OH OH OH HN Cofactr A OH HO OH CH CH HN HN OH HO HO HO OH HN

A chemist is studying the following equilibirum, which has the given equilibrium constant at a certain temperature N,(g) 2H,0(g) 2 NO(g) 2H, (g) K, 5. x 10 He fills a reaction vessel at this temperature with 11. atm of nitrogen gas and 8.4 atm of water vapor. Use this data to answer the questions in the table below Can you predict the

Complete the reaction. Add hydrogen atoms and charges to the appropriate atoms. HCI H. CH3CH2CCH3 heat H

What is the electrostatic potential energy (in joules) between an electron and a proton that are separated by 52 pm?

Fill each box below:

fil ach bas balow Draw the ENANTIOMER Find all of CHIRAL Isit a MESO Name cach centers form CHIRAL center fit eists IRor Sif may sist) Ranemier mene Crde or label fthey exist YESNO termu de nat have mantanna

What is the major organic product formed in the following reaction CH3 Br C,HO CH3 CH3 (A) (B) CH3 CH3 CH3 (C) (D) and D.

Calculate the net yield and the specific substrate degradation of a microbial culture that consumes 4,15 g L1.di of arabinose, having a true yield of 0,593 g cells g arabinose and decay rate of 0.195 d1. Concentration of microbial cells in the reactor is 1,78 g L. Finally, calculate the maintenance energy when the substrate is almost completely

The following reaction could in theory provide more than one type of product. Using the given spectroscopic information, provide the structure of the product that is formed. For full credit, show how the spectrum is consistent with your proposed structure. AICI, PPM Inteerals S1111113

Give products. HO. H,SO, a. HNO3 FeCl, Cl, C. AICI, H,SO, d. OH so3 Zn(Hg) HCI

How would you carry out the following syntheses HO, a. b. HCECH ECH CHCH2 CH3 . HO

Give the products of these reactions. 1) LIAIH, 2) H,0 a. b. HIO4 OH 1) LIAIH . 0 2) H,0 NABH, d. C CH,OH Oso, BU0OH OH pyridinium f. chlorochromate 12 g. 2 SH base H,02 h. SH NaHCO,

Consider a stoichiometric mixture of H and O at standard condition (298.15 K and 1.05 x 105 Pa,) at the upstream. The specific heat ratio of the mixture is 1.4. The heat of combustion for this stoichiometric mixture qe is 190.5 kJmole. The universal gas constant R 8. 314 Jmole K. (1) calculate the average molecular weight of the mixture MW, the

Analyze IR spectra of glycerol and ethyl cis-9-octadecenoate.

18. Which sketch best represents the qualitative molecular view of a weak acid (Water molecules are not shown explicitly.) a. d.

In an upright vessel contains 5 tons of coal at a temperature of 1200 C. Steam flows from below with a temperature of 200 C in a supersaturated state. As a result, a reaction occurs between steam and coal. The product of the reaction comes out of the vessel at a temperature of 800 C with the following composition CO2 6,5 CO 39,7 H2 53,5 The

A 55.0 mL solution of 0.0200 M triethanolamine is extracted with 115 mL of solvent. The distribution constant for the reaction is 4.00 and the pKa of the protonated form of triethanolamine is 7.762. Calculate the concentration of triethanolamine remaining in the aqueous phase at pH 6.50 and pH 8.50. triethanolamine at pH 6.50 M triethanolamine

17. What is the mass percent () for O in SO2 (b) 45.41 (a) 38.09 (c) 50.00 (d) 53.86 (e) 56.43 18. Which of the following is the empirical formula (a) CSH18 (c) C4H1002 Hint Empirical formula is the simplest integral ratio among each atom. (b) CH3COOH (d) NH4NO3 () 6 19. Chemical analysis shows the composition of a compound containing carbon,

Randy Giuliani petitions the court for Chapter 7 bankruptcy. The total cash value of his assets is $115,000 as of the date of the filing. The bankruptcy trustee later is able to recover $20,000 by setting aside a fraudulent conveyance and Randy receives a gift from his sister in the amount of $10,000. He has $15,000 in exempt assets (which is

Fill in either the appropriate final product or necessary starting materials Diels Alder Reactions A HO, CO2CH3 D .CO2CH3 E F CO2H

How many atoms of hydrogen are in 200 g of hydrogen peroxide (H2O2)?

You have prepared a protein extract from a tissue, and before running an SDS polyacrylamide gel, you need to determine the protein concentration in the extract, so you know what volume of extract you need to load on the gel to give 15 g total protein. You dilute 10 uL of the protein extract with 90 uL of buffer and measure the protein

Acid Ionization Constants at 25C Name of Acid Ionization Equation K a Sulfuric acid H 2 SO 4 H + + HSO 4 HSO 4 H + + SO 4 2 very large 1.3 10 2 Oxalic acid H 2 C 2 O 4 H + + HC 2 O 4 HC 2 O 4 H + + C 2 O 4 2 6.5 10 2 6.1 10 5 Phosphoric acid H 3 PO 4 H + + H 2 PO 4 H 2 PO 4 H + + HPO 4 2 HPO 4 2 H + + PO 4 3 7.5 10 3 6.2 10 8 4.8

Calculate the change in pH when 8.00 ml. of 0.100 M HCI(aq) is added to 100.0 ml. of a buffer solution that is 0.100 M in NH, (aq) and 0.100 M in NH, CI(aq). Consult the table of ionization constants as needed. ApH Calculate the change in pH when 8.00 ml of 0.100 M NAOH is added to the original buffer solution. ApH

What happens when resorcinol is added to acidified milk containing maltose, as opposed to sucrose? Aside from acids in milk, ferric chloride can also be used to test the purity of aspirin. Describe how this test is carried out for aspirin and how to interpret the result.

A major component of gasoline is octane . When octane is burned in air, it chemically reacts with oxygen gas to produce carbon dioxide and water. What mass of carbon dioxide is produced by the reaction of of octane?

Fully deuteriated acetone (acetoneD6) is often used as a protonfree NMR solvent. However, it usually contains a small amount of acetoneD5. (a) Predict the appearance of the H spectrum of acetoneD5. (b) Predict the appearance of the 13C spectrum of acetoneD6 27 acetoneD EXAMPLE 8.13 From your knowledge of heteronu clear coupling, predict which 3CH

a. Identify the functional group. b. What is the molar mass c. What is the empirical formula d. What is the structure LOD D. 4000 3000 2000 1500 1000 500 HAVENUMB ERI 1l TRANSMETTRNCEI Relative Intensity ,100 MSNU0661 80 60 40 20 10 30 40 50 60 70 80 90 100 mz Relative Intensity 20 ,11 10 7 4 3 2 1 0 HSP01218 ppm 00

What steps would you take to carry out these transformations a. H b. C. H 10

5) The following reaction takes place under acidic conditions, transferring an acyl group from the more stable, less reactive amide to the less stable, more reactive ester. Provide a brief explanation for why this reaction works despite seeming to go against thermodynamic principles (2 points) HO acidic solution HN, NH2 Explanation

The structures of two isomeric natural products are shown below. Zingiberene has Amax 229 nm, while Bcurcumene does not absorb in the UV. Which structure is which compound Explain your reasoning. . b.

What reagent would be used to carry out this reaction OH O chromic acid peracetic acid O hydrogen peroxide O osmium tetroxide O periodic acid Question 9 What reagent would be used to carry out this reaction OH HO. chromic acid O iodine O periodic acid O osmium tetroxide

Show the reactants needed to produce this product via the Grignard synthesis. OH

Draw the mechanism for the sulfuric acid catalyzed formation of diethyl ether from ethanol.

Which of these compounds will react with NaBH4 . D A U DC SOH

What is the product of the reaction CCI3 A . Cl3 CHCI, base ... D. CI O A C.

What reagent would be used to carry out this reaction OH HO, O chromic acid O iodine O periodic acid osmium tetroxide

What reagent would you use to carry out the following (single step) reaction CI

What reagent would be used to carry out this reaction HS. SH O osmium tetroxide O periodic acid O chromic acid O iodine

What is the product of the reaction A S . H,O2 and SH base C. SH D. HO O A O C O D

Which of these cannot be oxidized by chromic acid OH . b. C. d. OH O d O a O c O b

Select the correct structure for the 13C NMR below you A C B 1C NMR Spectrum (50.0 MHz. CDCI, solution) expansion 135 130 ppm DEPT CHt CHt CHt expansion 135 130 pom proton decoupled solvent 200 160 120 0 8 (ppm) 80 40

a. Drive the temperature equation depending on one variable only. Justify through example. b. Estimate the thermal conductivity of vapor at 713k and 130 atm

7) Draw the product of each of the following Sigmatropic rearrangement. Show the intermediates if necessary. Show your work by drawing arrows heat heat b)

The structure below represents a tetrahedral alkoxideion intermediate formed by addition of a nucleophile to a carboxylic acid derivative. ball stick labels In the window below, draw both the starting acid derivative and the ultimate carboxylic acid derivative product. Do not include the product formed by the leaving group. Use the wedgehash

1) Given the R graph (left) and the Y plot (Right), identify the orbital and draw the 90 probability cross section R 10 20 30 Y a) What does the line on the vertical axis on the Y plot represent b) At what r value (r) is there a radial node c) How many radial nodes does this orbital have d) How many angular nodes does this orbital have e) What is

Use a spreadsheet to calculate the potentials and construct a titration curve for the reaction of 50 mL of 0.10 M Fe 3+ with 0.050 M Sn 2+ . Assume that the [H + ] = 1.0.

Calculate the potential for the following cell using : a) Concentrations b) Activities Cr|Cr2(SO4)3 (2.25X10-2 M), PbSO4 (sat'd) | Pb

First consider the melting of gallium: Ga(s) Ga(l) a. Consider the following entropy data for gallium. S(liquid) 59.25 J/mol*K S(solid) 40.83 J/mol*K Calculate the entropy change for the system. Show labelled work! b. The H o fusion for gallium is +5.58 kJ/mol. Calculate the entropy change for the surroundings, assuming T=25 o C. Show labelled

12. Show how you would synthesize CH3CH2COOCH2CH3 from CH3CH2COCI. (2 points) 13. Give the final product for the following sequence of reactions. (2 points) 1. CH,H,NHCHCH3 2. NABH,CN CH3 3. H20

From the information provided, use cell notation to describe the following systems. (Include states ofmatter under the given conditions in your answer.) (0) In one half.cell, a solution of Pt(NO), forms Pt metal, while in the other halfcell, Mg metal goes into a Mo(NO), solution with all solute concentr chemPad Help Oreek (b) The cathode consists

Which one of the following options correctly ranks the acidity of the depicted compounds Select one Ha HVCHCO,H CH,CO,H CH,CO,H O b. Ha HaCH,cO.H O,COH CH,CO,H H Ha aCH,cOH ICHCOH CH,CO,H HHa ICH,COH aCH,CO,H CH,COH ICHCOH H CCH,CO,H Ha CH,COH

The critical potential for stresscorrosion cracking of moderately coldworked 188 stainless steel in deaerated MgCl, solution at 130C is 0.145 V (S.H.E.). (a) What effect on SCC of 188 results from coupling to nickel (0.corr 0.18V) (d) On adding HCl Why (c) Under (b), below what value of pH at 130C does the cathode potential of 188 become more

A COMPOUND WITH A mocEcuLAR WEIGHT OF (80 AMU GiVES THE FOLO WNG DATA. How MAN CARRON ATOMS DOES THE (OMPOUND CON TAIN RELATIVE nHTENSITY 3.8 00,0 . 1.3 1530 B0,0 181.0 132.0 B.)12 D) 14

Write the structure(s) for the organic product(s) of the carbohydrate reaction below. ball stick v labels HOCH2 CH3 dilute aq. HCI HO.. OCCN H3 OH Linamarin Use the wedgehash bond tools to indicate stereochemistry where it exists. If two diastereomers are formed, draw both. If no reaction occurs, draw the organic starting material. Draw

Draw all constitutional isomers of molecular formula C7H6B12 that are aromatic

Bromine is one of the few elements that is liquid in its standard state. Though quite polarizable, its boiling point (59C) is well below that of water, hence it has a high vapor pressure at room temperature. Thermodynamic data is available on the formula sheet. Br2(1) Br2(g) a) 4 pts Estimate the temperature at which K for vaporization is 1.00.

Describe a sample preparation combined with direct high performance liquid chromatography (HPLC) method for the separation and determination of the analytes (suggest column packing, mobile phase, solubility of analytes in mobile phase and detector that would be the most suitable). Provide justification for your answers. CH, CH3 H2N H,N SMZ SDZ pKa

Which would be the best representation of a mixture containing helium and chlorine gases? drawing

An equal number of moles of Na,CO is added to four different 10.0mL samples. Sample 1 Sample 2 Sample 3 Sample 4 0.50 M Ba 0.50 M Ca (ag) 0.50 M Mg (ag) 0.50 M Sr (aq) A precipitate forms in only one of the samples. Identify the cation which is present in the precipitate. . B. Ca2 C. Mg D. Sr 2

An equal number of moles of Na,CO is added to four different 10.0mL samples. Sample 1 Sample 2 Sample 3 Sample 4 0.50 M Bae 0.50 M Ca (ag) 0.50 M Mg (ag) 0.50 M Sr (ag) A precipitate forms in only one of the samples. Identify the cation which is present in the precipitate. A. Ba B. Ca2 C. Mg D. Sr 2

Draw the product.

1. Hg(OAc),, H,0 2. NABH,

Draw the product.

H,PdC

Draw the product.

1. OsO, 2. NaHSO,, H,O or OsO, NMO

write the IUPAC name of the following compounds

CH CH CH CH CH CH2

Write the IUPAC name of the following compounds

CH3 H3C CH3 H2C